The Cutting Phase in
tanzanite

Fifty-eighty-five million years. Mother Nature required this much time to form one of her most precious gems in the foothills of Mount Kilimanjaro. To comprehend the true nature of this stone, we must first comprehend how Mount Kilimanjaro was formed.

The process by which it formed is known as regional metamorphism, and it can be defined as follows: when tectonic plates collide, the igneous rocks (rocks formed by cooling and solidifying magma/lava) on each plate are transformed into one another by intense pressure. When the rocks reach the melting point, they form magnificent crystal structures.

The circumstances that led to the formation of this pure gem were so special that geologists believe that the chances of finding another batch of tanzanite in another part of the world are less than one in a million!

The pleochroism of Tanzanites is well known. They do, in fact, have the distinct ability to show different colors when viewed from different crystal directions. This is why, when cutting the stone, the cutting guides must be meticulously followed, since they will decide the overall face-up color of the stone. Cutters do not apprehend their cutting process in the same way as they do with other gems.

When deciding how to cut tanzanite, financial factors are important. Indeed, lost weight equals lost revenue. They must exercise extreme caution before initiating any action. Fine cut tanzanite usually yields up to 30% of the premium over cut stones when weight maximization techniques are used. To save money, cutters generally try to emphasize the violet-purple color because it is less difficult than cutting tanzanite to produce a violet-blue hue.

This explains why face-up violet-purple tanzanites are more commonly found on the market than those with a greater blue color component.

With more than a decade of marketing experience, I am now based in Bangkok where I combine my professional background with a long-standing passion for gemstones. I write articles that explore both the beauty and the business of gems, offering insights into their history, trade, and market dynamics. My goal is to make the world of gemstones more accessible to anyone curious to learn, while bringing in the perspective of someone who understands both storytelling and strategy.