You may not have heard of the gem Tanzanite, but that's because there hasn't been much time for the word to get around. Discovered only five decades ago, Tanzanite is among humankind's new found favourites. It has a one of a kind multicoloured, blue to violet to burgundy appearance, determined by crystal structure. This amazing appearance is incomparable to other gems.What are the Properties of Tanzanite?
Faceted Tanzanites are typically eye-clean, meaning there are no visible imperfections to the naked eye. Gems that do not qualify as eye-are often significantly cheaper or are selected to be used as cabochons or beads. Tanzanite is a coloured gemstone and there are often difficulties in grading it. Few organizations agree on the specific grading rule that should be used for these gems, though grading scales do exist. Perhaps the best known, developed by The Tanzanite Foundation, grades the stones based on the hues of violet, blue and brown.
Tanzanite may be the next big thing, but it can already get pretty big. The largest rough tanzanite weighed in at nearly 7.5 pounds! That's over 16,000 carats worth of vivid blue-violet.
However, the vast majority of tanzanite found is granular in size. At around a 6.5 on the Mohs scale of hardness, Tanzanite isn't among the hardest of gems and should be treated with care. Because of its fragility, it shouldn't be cleaned using a steam or ultrasonic machine; nor should it ever come in contact with acid. Sudden, drastic changes in temperature can lead to cracks within the gem caused by rapid expansion or shrinkage.
Everyday use in items of jewellery, especially rings can also lead to wear and damage.History
In a process requiring millions, upon millions of years, Tanzanite deposits formed within throwing distance of Mount Kilimanjaro. It is believed that the conditions for its growth were caused by an eruption of Kilimanjaro hundreds of millions of years ago. In terms of occurrence, Tanzanite is estimated to be more than one thousand times rarer than diamond. The first known Tanzanite was mislabelled as other gems and minerals numerous times before finally making its way into the hands of the Gemological Institute of America, where it was identified as a new variety of zoisite.
Its scientific name "blue zoisite'' lacked commercial appeal and romance so, Tiffany & Co. decided to rename it after the only place on earth that it has been found, Tanzania. This exercise in branding transformed the gemstones fortunes. Tiffany's began the first public awareness campaign for the stone in 1969, and soon blue zoisite would be universally known as Tanzanite. Tiffany's never could have dreamed the impact that this campaign would bring
Realizing that it was incredibly unique, in appearance and location mined, the public began their insatiable consumption of tanzanite. Toted as the "gemstone of the 20th century", gem enthusiasts the world over craved to see, hold and possess tanzanite. Of course, however, it wasn't only experts who lusted after the gem. Even without knowing its name or origin, members of the general public could see tanzanite as it was: an unprecedented mineral, like no other before it. In 2002, tanzanite was adopted as the official birthstone for December by the American Gem Trade Association (AGTA). This makes it the only addition to this list in over a century, and the only gem discovered in those years to be added to the list.Colour
Without its colour, Tanzanite would just be zoisite. However, its colour is so exclusive that is affiliation with the common Epidote group is typically forgotten. In fact, its colour could be more accurately described as an aura. Rather than emitting a single colour, Tanzanite glows with a rainbow of blue and purple. Often described as being blue, surrounded by hints of purple, the colour of Tanzanite may vary. As stated earlier, the formation in which the crystals coalesced determines whether the gem will be a light blue, lilac, deep indigo or violet stone. The blue within the gem is easily revealed by using fluorescent light, while the purple may be highlighted using incandescent light. Simply viewing the gem from several angles, one can make out they different colours trapped inside. This ability to be multiple colours at once further differentiates Tanzanite from other gems. In the world of rare minerals, any distinguishing feature adds to the stones rarity and value.Where is Tanzanite Mined?
The uniqueness of its appearance is matched only by the uncommon way this stone is collected. All of the Tanzanite discovered on Earth has been collected in the Mererani Hills of Tanzania. In order to retain the economic prosperity Tanzanite brings about, Tanzania have adopted legislation limiting the amount and size of rough material that can be exported. It's understandable that this region would have some special geological features, since only a few miles away lies the highest free-standing mountain in the world, Mt. Kilimanjaro. This extreme geographical region houses the only mines in the world where Tanzanite has been found. Extraction often takes place in small mines, few of which use modern equipment. Roughly half of the mines are owned and operated by local companies, while the other half are owned and operated by large corporations.
Due to its relative fragility, some common methods of treatment cannot be performed on Tanzanite. The most prevalent way to treat Tanzanite is through heat. Around 700''''''' in a furnace for 30 minutes, the burgundy within the Tanzanite begins to fade to make way for the sought-after violet-blue hue. This process of treatment transforms the trichroic, dim tanzanite into dichroic, brilliant tanzanite. Perhaps the best part of the heat treatment is its permanence in changing the gem's hue. Additionally, a Tanzanite gem that is untreated, but is naturally blue-violet is bound to be extraordinarily more expensive than a treated Tanzanite of the same quality and size.
About the Author:
Edward Fleming is a bespoke jewellery designer and ethical gemstone seller based in London. To find out more about ethical jewellery and gemstones visit http://www.edwardflemingjewellery.com