รายละเอียด: แทนซาไนต์ (Tanzanite) มีสีน้ำเงินอมเขียว อมน้ำตาล โดยสีเปลี่ยนตามทิศทางผลึก แทนซาไนต์ (Tanzanite) มีลักษณะคล้ายกับไพลิน (Blue sapphire) มาก แต่แสดงสีแฝดที่เด่นชัดกว่า มีค่าดัชนีหักเห และ ความถ่วงจำเพาะที่ต่ำกว่า อัญมณีที่มีสีเหมือน Tanzanite อีกชนิด คือ Iolite แสดงสีแฝดเด่นชัดเช่นกัน แต่แยกได้โดยมีค่าดัชนีหักเห และ ความถ่วงจำเพาะต่ำกว่า Tanzanite อยู่ในกลุ่มของ ซอยไซต์ (Zoisite) ซึ่งเป็นแร่ที่มีหลายชนิด ที่จัดเป็นอัญมณี มีสีคล้ายไพลิน โดยสีเกิดจากธาตุ V เป็นอัญมณีที่แสดงสีแฝด (pleochroism) เด่นชัด เกิดในหินแปร โดย แทนซาไนต์ (Tanzanite) พบในหินที่แปรสภาพมาจากหินปูนบริเวณที่แทรกสลับกับหิน Schist มีความแข็ง (Hardness) = 6.5-7 โมฮส์ (Mohs) ส่วนประกอบทางเคมี (Chemical Formula) = Ca2Al3O(SiO4)(Si2O7)(OH), Calcium Aluminum Silicate Hydroxide ดัชนีหักเหของแสง (Refractive Index) = 1.696-1.718 ความถ่วงจำเพาะ (Specific gravity) = 3.3
Displaying an aurora of stunning blues and violets, Tanzanite's popularity is well deserved. Demand for Tanzanite has rocketed in recent years, outstripping sales of all other colored gemstones, with the exception of Sapphire. A thousand times rarer than Diamonds and with a little over a decade of mine life remaining, Tanzanite is the fashion gem of the millennium. Legends and loreWhile Tanzanite might not yet be the stuff of legends, being discovered a mere 40 years ago, this gorgeous gem has already attracted more attention and gossip than any modern-day celebrity. Named for Czechoslovakian Baron Zois von Edelstein, before Tanzanite, Zoisite (Tanzanite's gemological name) never really amounted to much. Sure, opaque pink and apple-green varieties were used in jewelry, but these were never going to make Zoisite hugely popular. All this changed in 1967 at the arid foothills of Mount Kilimanjaro in Merelani, Tanzania. Legend has it that a short lived grass fire caused by a lightening strike was the catalyst that turned burgundy violet surface pebbles of Zoisite into the vibrant blues spotted by Tanzania's nomadic Masai herdsmen. While wonderfully romantic, it is unlikely a grass fire could affect such a dramatic transformation. In reality, the story of Tanzanite's discovery is as fascinating as the gem. While it is not known exactly who first found Tanzanite, the most popular story is that a local tribesman, Ali Juuyawatu discovered a translucent Tanzanite crystal at the base of Mount Kilimanjaro, sharing his find with a local prospector named Manuel D'Souza. D'Souza was actually searching for Rubies in the region and initially thought he'd discovered a new source of Sapphires. However, their multitude of blues and complex composition soon revealed Tanzanite's true identity to gemologists. Interestingly, the legendary Scottish geologist, Campbell R. Bridges, first discovered Tsavorite in Tanzania in 1967 during some Tanzanite consulting work for Tiffany & Co. and was the first person to bring Tanzanite to the US for identification by the GIA (Gemological Institute of America) Gem Trade Laboratory. Tanzanite quickly found its way to American jewelers, arriving at the New York-based jewelers Tiffany & Co. Henry B. Platt, great grandson of Louis Comfort Tiffany and later President and Chairman of Tiffany & Co., was immediately enraptured by its beauty, but disturbed by its gemological name "Blue Zoisite." To him the name echoed "blue suicide." As with everything, it's all in the name, so this rare and exotic African gemstone was christened Tanzanite. At Tanzanite's official launch in October 1968, Platt remarked that it "was the most beautiful blue gemstone discovered in over 2,000 years." Heralded as "the gemstone of the 20th century," Tanzanite's blue-purple fire soon took the world by storm and demand for Tanzanite jewelry grew dramatically, until in 1998 and 1999 Tanzanite was proclaimed the world's best selling colored gemstone. Today, the demand for Tanzanite continues, outstripping sales of all other colored gemstones, with the exception of Sapphire. In recognition of its popularity, in 2002 Tanzanite was added to the jewelry industry's official birthstone list. This saw Tanzanite join Turquoise and Zircon as accepted birthstones for December. Not a small thing, especially when you consider this was the first time the list had been changed since 1912! Now an official birthstone, Tanzanite is increasingly regarded as the ideal gem to celebrate new life and new beginnings. This belief has its roots in Masai tradition, where blue is believed to be a sacred spiritual color and bestowed in the form of blue beads and robes to women who have borne children. Today, this tradition has evolved, with Masai chiefs giving Tanzanite to wives on the birth of a baby. This gift is believed to bless their child with a healthy, positive and successful life. Tanzanite continues to be all the rage in contemporary jewelry. Tom Ford, formerly "enfant terrible" of the Paris and Milan fashion house Gucci, once dominated the catwalks with a collection modeling exotic blue gems, including Tanzanite. At the 2004 Oscars, Eileen Penn, mother of OSCAR® winner Sean Penn, stole the limelight from her son with a stunning Tanzanite and Diamond cross pendant. Just the factsA key ingredient in Tanzanite's success is that it exhibits more shades of blue than a clear midnight sky due to a phenomenon called pleochroism, whereby different colors are seen in different directions of the gemstone. Tanzanite is extremely light sensitive, frequently exhibiting a color shift from more bluish hues under daylight, to pinkish violets under incandescent lighting (candlelight). While the best examples show an intense blue under any light, most of the time, you can actually see both colors simultaneously. As an allochromatic (other colored) gemstone, color saturation in Tanzanite is determined by the amount and ratio of chromium and vanadium trace elements. Whether you choose a pastel or richer colored Tanzanite is down to your preference and budget, but please be aware that Tanzanite's colorful brilliance intensifies in larger sizes - you're generally not going to find deeper colors in smaller sizes. As Tanzanite crystals occur with reasonably few inclusions, the standard is eye-clean (no visible inclusions when the gem is examined approximately 6 inches from the naked eye). Tanzanite is found in a variety of shapes and cuts. Ovals and Cushions are the most common, but Rounds and other shapes are also seen. Regardless of the cut, look for good brilliance. While intense blues are favored, overly large or poorly cut examples can loose brilliance, making them appear too dark. Tanzanite can sometimes occur in extremely large sizes, but the most popular sizes for jewelry are below 20 carats. Tanzanite's wonderful colors, clarity and range of imaginative cuts lend itself to prominent display. While fashionable drop-earrings and pendants accentuate Tanzanite's inherent characteristics, it's also popularly featured as large carat-sized solitaires mounted into prominent ring settings that show off its scintillating colors to full effect. Exclusively mined in one deposit in East Africa in an area of Tanzania known as Merelani, Tanzanite is also coveted because of its rarity. The conditions involved in Tanzanite's formation 585 million years ago saw the random incorporation of vanadium during an event so unique that experts believe the chance of Tanzanite occurring elsewhere is one in a million. The Tanzanite deposits are hosted in metamorphic rocks, marbles and schists that belong to the Mozambique Belt (Rift Valley). The deposits run through the low hills of Merelani that rise from the hot Sanya plains, close to Mount Kilimanjaro. Running at an angle of 41 degrees to the surface, the deposit line or horizon periodically folds over itself, creating pockets of Tanzanite. Barely covering 8 square miles, the Tanzanite mining area has been divided into four different sections known as "blocks" (lettered A, B, C and D) that have been allotted to different mining groups. Even at the largest and most sophisticated mine in operation in C block, the yield for raw Tanzanite crystals average only 22 carats (4.4 grams) per processed ton! Tanzanite production is slowly, but surely decreasing and many experts believe Tanzanite will disappear in years to come. Understandably, this has led to Tanzanite gaining considerable notoriety. After all, the desire to own something beautiful and rare is irresistible. Although there are several Tanzanite grading systems available, they are all primarily concerned with judging color quality. This is because compared to Ruby, Sapphire and Emerald, Tanzanite is typically free from inclusions, making color the single most important factor when evaluating Tanzanite. Representing less than 1% of all Tanzanite mined, AAA Tanzanite is characterized by intensely deep purple blues and can be likened to an old French wine of an impossibly hard to obtain vintage. Interestingly, the D block section has earned the reputation for supplying the majority of AAA Tanzanite. AAA Tanzanite is the very best quality Tanzanite sold at GemsTV. As Tanzanite typically starts its life as bluish burgundy crystals, virtually all Tanzanite has been heated to enhance their color. This is an accepted and permanent treatment that actually makes Tanzanite's color-causing element, vanadium, more stable. Occasionally, this process produces highly coveted and extremely rare fancy colors (Pink Tanzanite, Green Tanzanite, Multi Color Tanzanite etc.). Possessing all the qualities of regular Tanzanite, these colored varieties are far less common and are highly coveted by collectors. In gemology, the technically correct name for these gems is "(Color Prefix) Zoisite." However, "(Color Prefix) Tanzanite" is generally accepted in the marketplace due to the gem's popularity and because this name specifies an origin. Tanzanite exudes sophistication, individuality and self confidence. Tanzanite jewelry is suited to all ages, emphasizing the nonconformity of the young and the sophistication of the mature. However, Tanzanite is rare and growing rarer by the moment. Apart from the sheer pleasure of owning one of the 20th century's most spectacular gemstones, those fortunate to already own a Tanzanite, or to purchase one before the only known deposit is depleted, truly are custodians of a gem whose legacy will be to pass it on as an heirloom to future generations. THANKS ; GEMS TV |