Hi Marc, I have received the ring! It is very well made and gorgeous!! Love the sapphire from you!! Thank you so much for the time and patience!! I would have love it to be bigger, but with the budget I guess this is probably one that I should be glad. Still I am very happy with the overall colour and clarity of the gemstone!! It does exhibit different saturation under different lighting. Most importantly the cut is great!! Attached a few pics taken by mobile phone under shelter in daylight. Thank you once again! Will definitely recommend you to any of my peers if they need gemstones purchases! Jordan W. of Singapore (bought loose sapphire and custom ring)
Marc, The aquamarine stone arrived today. It is truly an exceptional stone. As a collector for the last 14 years, I never thought I would be able to get to own an aqua with such saturation that I could afford. Again, it is a pleasure doing business with you. Best regards, Ted K of Totowna NJ (bought super gem aquamarine stone)
Marc - thank you very much. I cannot tell you how much it means to me for you to go to the effort. Tomorrow is my girlfriend's birthday, and I hope to give it to her at lunch - a special lunch, of course. She loves stones of all kinds, precious and semi-precious. I see stones and I think they're nice, and pretty. But she sees something else, something connected to the Earth, to history, and all things like that. She can stare at the stone for hours. Which, hopefully, she'll do it tomorrow at lunch. Thank you once again for saving me in the last moment. Royston T. of canoga park, CA (bought loose blue sapphire)
No problem at all Marc, These things happen. I really can't speak highly enough of the service you have provided considering the distance. All the best. Jake P of London UK (bought custom green beryl ring)
Hi Marc, Thanks very much for all your help. Finally managed to get a good look at the stone, whilst not perfect, I do love the imperfections! The little swirl in the middle - great stuff. Not sure if there's anything required from my end to complete the sale, would like to get to this to the goldsmiths to be set. Once again, thanks so much - it'll certainly make one girl very happy. Regards, Mike W from Singapore (bought blue sapphire gemstone)
Thank you for everything Marc. I received the FedEx this morning, the stone is beautiful. It's exactly what I wanted for my wife's birthday! All the numbers look good to me. Again I am very impressed with your gems and your customer service. My daughter is already thinking about what she might like for her 16th birthday! All the best, Dave A from Lafayette LA (bought aquamarine studs)
Hi Marc, Thank you, got it. She loves it, and said yes!:) Cheers, Jadel M from Vancouver Canada (bought topaz ring)
Hey Marc Merry Christmas. Just want to thank you for the timely delivery. Lisa adores the earrings and ring and couldn't be happier.They both display quality and beauty, needless to say I'm happy as well. Thank You Ryan S from Peoria IL (bought various custom jewelry)
Hi Marc, I just got home from work and my husband said, Come look. On the window sill in its box was the Blue Zircon. It had just arrived. The invoice and certificate arrived yesterday. How absolutely beautiful, it’s all that I was looking for!!! I love the color and the cut. Is this a step cut? Anyway, I just love it and so does my husband. I really appreciate your expertise and your patience in helping me make this choice. I did look at other sites, but something told me to stick with you and I’m so happy that I did. P.S. My husband, Gary also said that if you ever think of renaming your company, his suggestion is STUNNING GEMS! I second that and will highly recommend AFRICAGEMS to others. All the best to you and your company. Brenda H. of Boston MA (bought loose blue zircon)
Marc, Received the spinel today and was very impressed. Although I do own some spinel, nothing in my collection has the eye-popping color of this stone. I say this knowing that pink isn't necessarily my first choice as a color for a colored gemstone. It will make a nice addition to my collection. Ted K. of Pasadena CA (bought loose pink spinel)
I received my ring today and am absolutely delighted with the colour of the stone and the sizing is nearly as wonderful. Thank you so very much! Sonja C. of Charlotte NC (bought loose aquamarine)
Marc, the ring is amazing! Thank you for everything. The stone is truly incredible. Take care and I will certainly share your information whenever I get the opportunity. Mike B of Detroit MI (bought custom aquamarine ring)
Thank you very much for the work you put into our order, I gotta tell you I've had a blast playing around with the different features of your website, designing different rings and such. Your website is merchandised pretty good. Tracie loves the rings the ruby has got a real good glow out in the sunlight and the spinel looks wonderful in its mount. The only real problem is the chain on the necklace it came terribly tangled and me thinks we just made it worse but no biggie we had an extra chain. Overall very pleased with order. Thanks J. Sitton of Baton Rouge LA (bought 2 custom rings)
Yellow sapphire received. I must say I expected the comment about it being very diamond looking to be a bit of exaggeration that tends to occur with sapphire, but it is exactly that, yet unique in its brilliance and flash. I am very pleased with the stone and moved to send a compliment. John H of Indiana PA (bought yellow sapphire loose gem)
My ring arrived yesterday. It is beautiful. I've been running around the house looking for different light sources to view the colour change under. Thank you so much for your help and patience. I hope I have the opportunity to purchase another item from you again sometime. Jacquie A. of Vancover CA (bought custom alexandrite ring)
Hi Marc, My little diamond has just arrived safely by FedEx and it looks beautiful, thank you so much. It's as white as I hoped it would be and the bow tie isn't that obvious because of the size of the stone, I imagine. I'm now going to have the pleasure of thinking up a setting for him. Thank you very much, I'm delighted. I think I'm going to have to keep looking in your discounted stones section! Best wishes, Lynn M of Sufflock UK (bought loose diamond)
Hi Marc, I just wanted to thank you so much for everything you've done for us with the whole ring processes. I proposed to my girlfriend on Friday, and she beyond loved the ring. Everything came out perfectly, the sapphire is stunning, and the ring was set beautifully. Thanks again! Sincerely, Lukasz S. of Chicago IL (bought loose blue sapphire & custom ring)
Hi Marc, My gem has finally arrived and it is fabulous! The colour is exactly what I had hoped it would be.... Resembling sunset and lotus flower. I inspected the packaging and nothing appears to have been tampered with... I was getting concerned but looks like all is ok. My plan is to take the pad to a local gemologist to verify and then on to Designing a ring setting. This is a retirement gift to myself .... My last day at work is just before Christmas...so hopefully the ring will be ready by then. When it's done I will send you some pictures. Thank you for all your support thru this crazy process...although I've not met you I feel like I've known you for some time. I greatly appreciate your awesome Communication with me. I love the gem! Thank you Daria L of Ontario CA (bought loose padparadscha sapphire)
Marc, my ring has just arrived. I am over the moon. It is so beautiful. Thank you and your colleagues so very much. I am hoping it will bring me luck over the coming months as I am off the hospital this afternoon to find out about my operation for breast cancer. I'm sure it will help to protect me. Thank you, once again, for your brilliant contribution to my life. Warm regards, Shoosh S. of Birmingham UK (bought custom pink sapphire ring)
Hi Marc, This is Amazing! I've never experienced such fast shipping! I was noticed on a Wednesday that my items had been shipped, and on already on the following Monday I had the parcel at home! From US to Sweden in Europe! The Tanzanites I ordered are perfectly just what I requested! Thank you very much Marc! This means a lot for me! I will for sure recommend you further and come back for more orders! Wish you a nice day! Best regards, Queenie H. of Stockholm Sweden (bought loose tanzanites)
Hi Marc, I received my ring today. It fits perfectly, the color of the topaz is beautiful! I almost wish I had chosen a larger stone. Thank you, Mary A. of Modesto CA (bought a swiss blue topaz gold ring)
Cardy was AMAZING! It took 45 minutes. Everyone warned me that I would be without my ring for weeks, and you helped me get away from that. You have been extremely responsive and fantastic for all of this. I really appreciate you, and DEFINITELY would recommend you to anyone I can. You are very much running your business very well. Not to mention, my ring is beautiful!!! Exactly what I wanted. Katie F. of San Francisco CA (bought alexandrite engagement ring)
Hi Marc, I got my ring yesterday.. love it! Looks great! I like the way the prongs are done and the ruby is beautiful! Thanks, Brigitte L. (bought Chatham Ruby and AfricaGems made the ring)
Dear Marc, I have a confession to make. I lost my original engagement ring, a Stuller setting for an asscher cut and a cushion Chatham Sapphire. I wanted a ring that looked close to that original one. You made it happen! Actually, your mil grain work and stone setting was better than the original which was off centered. Thank you. Regards, Christine Y (bought Chatham Blue Sapphire and we made the ring)
Marc, Received the stone. It’s beautiful! We now have a new place to order stones from and feel confident in the quality! Thank You, Clayton M. (bought loose pink tourmaline gem)
Hi Marc, Thank you, I received the stone on Wednesday as you indicated. I appreciate the quick turn around time. Pleasure doing business with you and your site will be one of my top gem shopping sites after this business experience. I did enjoy the extra haribo snack. Thank you once again, Danny C. (bought a round 1 carat loose blue sapphire for engagement ring)
First diamonds are in the mail. Had gone away for a week and nobody at home dropped the mail in the box. Apologies. Picked up my pendant with the new ones and they look beautiful. My next purchase will be emeralds...Thanks, Marc. Li B (bought and exchanged enhanced blue diamonds)
Hi Marc, The bracelet arrived this morning and as you said it looks stunning and I know she will love it. Could you please send a Cert of Authenticity (Similar to the one sent for the 2 loose stones) and a full invoice for the total amount for insurance purposes at my end. If you need to send copies by post please send to, Alan H. (bought a tanzanite bracelet)
Hi Marc, I just wanted to say how delighted I was to receive the Tanzanite bracelet for Christmas. I understand from my husband, Alan, that you were extremely helpful with the making of the bracelet, it sounds like it caused a few problems at times, not least due to Alans bank! I just wanted to let you know that I am thrilled with the bracelet, the stones are beautiful and it looks lovely, so thank you for all your help! I hope you and your family had a good Christmas and very best wishes for a healthy, happy New Year. Kind regards, Sue H. (husband bought tanzanite bracelet)
Hi Marc, I just received the opal and it is gorgeous, as always I am very pleased with my purchase. I was looking at different pendants, it's a Christmas present for my daughter. I saw a multi-gem one that I liked. Item pendant 650870s. Should I order it on line or could you just do it. Also will you extend the 25 off discount on that item? Again, thanks for all your help,Terese U. (bought stunning loose black opal gem)
Good Afternoon Marc, Thank you so much selling me this amazing stone, I can assure you it will be well loved. I thought you might enjoy how much people love the blue spinel you sold me. I posted a few photos on PS last night and will likely post more in the next few days. Again thank you, I really do love it and I am wearing it even as I type this! Katherine S. (bought large blue spinel gemstone)
My wifes stone got here this morning. She was in awe of how gorgeous a stone it was. It is replacing a stone in a ring that was stolen and in our opinion we think it is even nicer than the stone it replaced. Once set we will be whole again lol. Again thank you for having the stone available and for you call concerning shipping. We will certainly recommend you to any of our friends who are looking for QUALITY stones. Doc Mc (bought loose oval padparadscha gemstone)
Hi Marc- just wanted to thank you for finding the 4.4mm size for me, and also for the quick refund on the 4mm. So glad I found your website! Cristy S. (bought loose white sapphires)
Hi Marc, I just want to say thank you so much! The pendant is so beautiful..well done! The bale also fits perfectly. I have a question about the negative ions created by tourmaline..now can one just wear it to experience the negative ions or does there have to be pressure applied to release the negative ions? I'm just curious. Thank you Dawn T (bought custom tourmaline pendant)
Marc, The ring arrrived yesterday and it is gorgeous! Thank you so much for creating the perfect piece with this sapphire. This ring will become an heirloom. Henry G (bought custom spessartite garnet ring)
Marc, Thank you so much! You may have thought it took longer than expected but we thought it was quite expedient. Thank you for continually confirming for us our decision to purchase from Africa Gems. This has been a wonderful transaction. We'll be here all day so as soon as it arrives I'll let you know. Happy Valentine's Day, Jennefer P of San Deigo CA (bought custom emerald ring & band)
I'll put them in the mail today. I want you to know that I really appreciate how amenable you have been. Your A+ rating is exactly right. I will continue to do business with you when I have other needs. My sister has also been checking out the site for sapphires based on the excellent service I received. Thanks again, Jim W.of Bangor MI (bought loose emeralds)
Will do! I'm in Denver on business until Saturday. I'll get it shipped out ASAP upon my return - next Monday most likely. Thank you for all of your help. Especially your guarantee and return policy. Made purchasing the gem online much more comfortable. Ironically, my jeweler also loosely knew your father and had a very good opinion of him. Thanks again Marc! Doug M from Camarillo CA (bought loose blue sapphire)
Marc, Your fantastic customer service makes it easy to support AfricaGems! Looking forward to surprising my wife with the Onyx ring. Regards, Michael S. from Boise ID (bought onyx diamond pendant)
Hi Marc, So far I'm very happy with the sapphire I purchased. My plan is to mount it in a tanzanite ring that I have (the tanzanite is very light in color and I've never been happy with it which is a surprise since it's also a Levian purchase). The setting has two sides with the stone suspended in between. I think the light will catch it magnificently! Thanks for checking on my order! Rita K. from Garland TX (bought Chatham emerald stone)
Hi Marc, Just to let you know that the stone was delivered today. Pitty it is dark now so can not see the true stae, but I am happy to see it here with the certs!I hope to do business with you again in the future! Thank you for you help, patience, Regards Wim D. of Dubai (bought loose oval alexandrite)
the rings have arrived they are absolutely stuning ! i thank you with all my heart and i pay no duties thanks to you THANK YOU VERY MUCH I HAVE NO WORDS TO THANKS !! Mencaglia A of Bucharest Romania (bought two blue topaz diamond rings)
Dear Marc, I just received the four turquoise gemstones that I had ordered. They are beautiful. I am very happy with the quality and will be ordering some more gemstones soon.Thanks Baljinder K. (bought loose turquoise gems)
Marc, I just wanted to let you know that I received the ring today and it’s beautiful, she’s gonna love it! Thank you again for all you’ve done. I was concerned about ordering something liker this over the internet but you’ve made this entire process very easy and your communication with me has been outstanding. Everything was exactly as you described it…perfect! David M. of Atlanta GA (bought custom Alexandrite diamond ring)
Tanzanites - Shopping for A Loose Tanzanite Gemstone? We Are THE Tanzanite Gem Stone Leader - AfricaGems Loose Tanzanites - See Our Low Tanzanite Prices Here - AAA Quality D Block Tanzanites - Full Calibrated Selection
Super Saturated Tanzanite Stunning Quality Pair in Trillion Cut, Vivid Blue Purple, 9.6 mm, 5.65 caratsThis Genuine Tanzanite Gemstone Pair Displays A Vivid Intense Rich Blue Purple, Excellent Saturation For The Size. Excellent Clarity, Cut And Life, A Beautiful Pair, Very Lively And Bright In A Hard To Find Rich Shade Of Color. A Great Find. Note For A Personal Detailed Description Of This Beautiful Tanzanite Gemstone Pair, Including Video, Please Contact Us And It Will Be Quickly Provided To You. Note The Very Facets That Create The Beautiful Sparkle In A Gemstone May Create Optical Illusion White Or Dark/Black Spots And Areas, Or Uneven Coloring When A Gemstone Is Photographed. Single Dimension Photographs Can Not Accurately Display The True Beauty And Life In A Gemstone. Gemstones Must Be Seen In Person To Be Appreciated. Note: Be Sure To Select The Right Gemstone/Diamond By Millimeter Size Only. Selecting Your Gemstone/Diamond By Carat Weight Is Not Accurate. The Best Way To Select The Right Size Gemstone/Diamond Is To Use Our Size Chart Image, Or Consult With A Local Jeweler To Measure Your Setting Or Gemstone. CLICK HERE FOR A SIZE CHART TO PRINT OUT (*Please set your PDF viewer to 100% for accurate results) Please Contact Us If You Have Any Questions.
See The Tanzanite Quality at AfricaGems - Amazing Deep of Color in This Fine 5 carat plus Super Gem
Tanzanite A Gemstone With a Beautiful Shade of Blue
Tanzanite is a rich in color, elegant gemstone prized for its exquisite ultramarine blue-violet color think of the most vibrant intense lapis lazuli gemstones only transparent. The color has been described by the American Gem Trade Association (AGTA) as a mesmerizing blend of rich purples and blues with a velvety deepness of color unlike any other gem. In the late 1960s and early 1970s, thanks to the famous jewelry store Tiffany's, tanzanite became the darling of the gemstone world.
Blue Zoisite - What Tanzanite Is Mineralogically
Tanzanite is a member of the zoisite family which was first identified by gemologists around 1800. The tanzanite (blue zoisite) branch of the family was not identified until 1967. The pink, yellow and green members of the zoisite family never became widely popular as a gemstone and were typically used for carvings and trinkets. Tanzanite (trichroic zoisite - blue / purple / salmon) is a very rare gemstone in that to date top quality tanzanite is found exclusively in the relatively small Merelani Hills area near Mount Kilimanjaro. Gem quality tsavorite and chromium-green diopside are also found in the area. This is not surprising since it seems that tanzanite and tsavorite form under very similar conditions but a different depths in the earth. There have been more recent discoveries of a few inky blue gem zoisite specimens found in the Tsavo region of Kenya, an area known for its exceptional quality tsavorite (green grossulargarnet). Those recent discoveries have so far amounted to just a few gemstones.
How Tanzanite Got It's Name?
It is believed that Henry Platt, the grandson of Louis Comfort Tiffany said at the public unveiling of tanzanite by Tiffany's that tanzanite was "the most beautiful blue stone to be discovered in over 2000 years." It is also the only gemstone to be added to the Modern birthstone list since the list was first created in 1912. It joins turquoise and blue zircon as birthstones for those born in December.
The History of Tanzanite - A Gemstone Whose Time Had Come
The history of the discovery of tanzanite is not simple. But one thing for sure, the fates or the alignment of the stars or destiny created a set of circumstances that ensured that tanzanite would be discovered and brought to the attention of the gemstone world hundreds or thousands of years after most gemstones used in jewelry had been discovered and identified.
Tanzanite Treatment - Tanzanite Is a Heat Treated Gemstone
In the beginning - Legend says that exposed brown or brownish yellow zoisite crystals in the Merelani area were heated by the periodic lightning caused grass fires that swept through the arid uninhabited area. Some will have you believe the grass fires would not have been hot enough to heat the exposed zoisite crystals, but some grasses do burn at temperatures over 540 degrees Centigrade and that is sufficient enough to cause brown zoisite to color change to blue in only two or three minutes. Add to that that there were repeated fires and that part of the legend could very well be true. As stated, that area is arid and before 1967 was for all intent, uninhabited. It was occasionally visited by Masai herders passing through, but it seems they paid no attention to the beautiful blue stones. 1967 was the year the stars aligned or the fates stepped in or a series of coincidences just happened and blue zoisite was officially discovered.
Manuel de Sousa - First Man To Recognize Tanzanite Value
Most people will agree that Manuel de Sousa (1913 - 1969) was the very first to file a claim to mine blue zoisite. It is believed that he was the first to recognize the primary alluvial (loose, sitting on the surface) deposits of zoisite crystals at Merelani and the first to recognize the potential value. Mr. de Sousa was an immigrant from Goa, India. He supported his family as a tailor yet was a man who dreamed of treasure to be found and as such, was a part time prospector. The actual details of how he found the deposit will never be known as he apparently told slightly different versions of the story to different people. It is not unusual for a prospector to embellish the story a little every time it is retold so this is understandable. He was consistent in his story that he was lead to the area by men native to the area, men who had no interest in the stones and that he found transparent blue stones dancing in the morning sun when he arrived at the area to which they had led him. He was also consistent in his story that he thought at first that he had found huge blue sapphires. Having been a prospector for years, one of the first things he did was to test samples of his find for hardness and discovered they were too soft to be sapphire. Using his mineralogy book and experience as a prospector, he decided that olivine was the closest match. Olivine was a semi-precious gemstone that was profitable to mine. Consequently, he staked out four claims of 1,000 feet by 1700 feet and on he filed four mining claims for olivine with the Government Mines and Geology office on July 25, 1967* and he began mining in earnest. By April of 1968 the gemstone world had correctly identified the gemstones as blue zoisite (tanzanite) and Mr. de Sousa re-filed the same four claims but for zoisite instead of olivine.
Word of Mr. de Sousaï's mining claims spread like wild fire and soon the area was inundated by prospectors / miners. It is believed that at least 90 claims were staked in a 20-square mile area soon after Mr. de Sousa filed his claims. According to a quote from Michael Wolf, Tanzania-Zoisite Corp. (May 9, 1969 Life Magazine Tanzania to Tiffany) ,it's all so bloody maddening. In the gem business, everybody loses his reason. You aren't dealing with rational men.
Like many discoverers of treasures, Mr. de Sousa had to deal with claim jumpers, workers that he hired stealing from him (he estimated they were stealing 80% to 90% of the gemstones) and then the guards he hired to stop the thefts were stealing from the workers and more. He seldom left his claims because of all this. Unfortunately, one time about 2 years after he filed his claims he left his claim and he lost his life in a car accident. It is interesting to note that due to many twists and turns of fate, government and other issues, none of the early zoisite claim holders managed to retain their rights.
The Tanzanite Star Is Born - Blue Zoisite, the GIA and the Smithsonian
Samples of blue zoisite made their way to the Gemological Institute of America (GIA) and the Smithsonian through different channels and unrelated sources at almost exactly the same time in 1967. Two of the first people to present samples to the GIA and the Smithsonian were Campbell Bridges, a British consulting geologist for Tiffany and Company and Hyman Saul, Vice President of Saks Fifth Avenue, who obtained samples from his son, John Saul, PhD, Nairobi-based consulting geologist. At the same time as blue zoisite was being analyzed by the GIA, samples of this new gemstone had made their way to European gemology laboratories for analysis.
Blue Zoisite - Tiffany's - Tanzanite
Blue Zoisite samples were also presented to Henry Platt by Hyman Saul and Campbell Bridges at almost exactly the same time. Henry Platt was Vice President of Tiffany and Company and their chief gem buyer and it was Henry Platt that decided that Tiffany and Company should present blue zoisite to the world through a major marketing campaign. He felt that this beautiful new gemstone would not go over well if it was presented under its scientific name and he renamed it Tanzanite in honor of its country of origin. In 1969 Tiffany and Company introduced Tanzanite to the US and the world of beautiful gemstone jewelry. And the rush for Tanzanite was on and it very rapidly became one of the world's most popular gemstones.
History of Tanzanite Production - Ups and Downs
In 1971 the tanzanite mines were nationalized. Beginning in 1971 and continuing for 20 years, production from the mines was very low mostly because of the problems of open-pit mining, bad management and theft. By 1986 it was believed that there were as many of 30,000 itinerant miners who had dug narrow shafts and tunnels throughout the area in search of tanzanite veins. In 1990, the Tanzanian government stepped in to try to bring some order to the area.
Terrorism and Tanzanite?
In 1998 and again in 2008, there was significant flooding with loss of life in the Tanzanite mines. In 2001 after 9/11, there was a temporary boycott of tanzanite by some jeweler in the US due to the incorrect belief that tanzanite was being used to finance terrorist operations. US intelligence agencies undertook extensive investigation into the issue and could find no evidence of Al-Queda involvement in tanzanite smuggling. In 2002, the Tuscon Tanzanite Protocol which established a tracking system for tanzanite was introduced to ensure conflict free tanzanites. Beginning in 2003, the government also instituted new safety regulations for the mines.
History of Tanzanite Prices
Tanzanite prices have also had their ups and downs. Prices were relatively low during the 1970 because tanzanite was not available to a large market but zoomed upward when in the early 1980's tanzanite was exposed to a larger market. As supply and demand leveled out, so did the prices. In the mid 1980's prices peaked and started dropping to levels that were lower than when Tiffany's had first introduced Tanzanite and thereby creating a new gemstone star in the industry. Prices had a roller coaster ride that continued through the 1990's due to over mining followed by closing of the mines by the Tanzanian government in an effort to stabilize the price, flooding and other issues. Tanzanite prices in the new century have been on the increase in part because it is unknown how long mine production will continue. Some believe the mines will play out in 10 or 15 years, yet there have been new reserves discovered in recent years so mining may go on much longer.
How To Judge Tanzanite Quality
By Color, Cut, and Clarity. Tanzanite is a beautiful trichroic blue / purple / pinkish-red gemstone. An American geologist was quoted in the May 1969 Life Magazine article as saying There is a predominant blue which is richer than a sapphire, a purple nicer than an amethyst and a pinkish-salmon-brown which is described by both Europeans and Africans as flesh-colored. This change of color depending on angle of viewing is what makes the cutting of tanzanite critical. The gem cutter needs to make sure to cut each gemstone so it displays the most blue and violet (purple) color.
Hue The best quality tanzanite is blue / violet. Some experts use a guideline of 85% to 90% blue (primary hue) to 10% to 15% violet secondary hue for the most desirable, expensive tanzanite. Light lavender with no secondary hue is the least expensive tanzanite. Using the GIA rating system, a ratio of 80% / 20% is probably the average for good tanzanite on the market today.
Tone The blue tone in a tanzanite should be between 75 and 80 percent to be ideal. Tanzanite should not be too dark or too light in tone. If they are below 60% they will appear as a washed out lavender color and those with tone above 80% will be very dark. Saturation - Saturation ranges from "grayish / brown" to "vivid". Think of the word "intensity" when evaluating saturation. There are 6 levels of saturation. Most experts believe tanzanite should a bright vivid blue or blue / violet with little to no gray.
Considering Buying a Tanzanite?
A buyer who is considering the purchase of a loose tanzanite gemstone should request a professional gemological report in order to help them know exactly what they are purchasing. Grading reports may be shown using a numerical value and / or percent of color saturation and for the clarity and color - it will depend on with which laboratory the gemologist trained. There are several recognized laboratories like Gemological Institute of America (GIA - uses the numerical scale), International Gemological Institute (IGI), International Gem Society (IGS), European Gemological Center (EGC) and more.
Clarity Tanzanite is a Type 1 gemstone and as such, it is graded very strictly. The best tanzanites are loupe clean or at the very least eye clean.
Synthetics or imitations To date, tanzanite has not been created synthetically. The most common imitation is blue-violet glass. One of the best ways to determine if the tanzanite you are viewing is genuine or not is to look for the red flash phenomenon. When viewed in incandescent lighting, tanzanite will tend to sift its color to the violet hue and flash red and / or pink color.
Enhancements Tanzanite is enhanced by heat-treatment which is permanent and stable. It is considered a natural enhancement that is a continuation of what Mother Nature started.
Durability - Tanzanite is 6 1/2 to 7 hardness on the Mohs scale so please take care to not just throw tanzanite jewelry loose into a jewelry box or don't wear while gardening or anywhere where it would be subject to hard knocks or scratching. Tanzanite is not as hard as sapphire and does require just a little more care.