One of the newest gemstones available today is also one of the rarest and most interesting of gems as well - Color Change Diaspore. This phenomenal gem was first cut and faceted into a gemstone in the 1980s, but only recently was it introduced to the international gem market on a commercial scale. Like most of the world's rarest and most precious gems, color change diaspore is found in only one location -- Turkey.
Its mineralogical name is diaspore, but when found in transparent gem-quality crystals, diaspore is traded as color-change diaspore - a name descriptive for its unique ability to change color when viewed under different light sources. Most color change diaspore will change from green with flashes of yellow under natural and fluorescent light. When viewed under incandescent lighting, the same gem changes to a champagne color; and when viewed under subdued (dimmed) lighting conditions, such as candlelight, diaspore will exhibit a delicate pinkish color.
With color change diaspore, larger stones usually have more pronounced and noticeable color change. The stung shift in color can be seen in very easily in top grade materials particularly well in cut stones over 1-2 carats. Diaspore in weights less than 1 carat still have color change, but the shift is not as noticeable -- sometimes simply because the stone is smaller for the eye to see it with.
Color-change diaspore was formerly branded as 'Zultanite', a trade name that was officially abandoned in 2012, but is still often used and heard today. The name Zultanite was assigned by the company that owned the sole rights to the diaspore mines, Zultanite Gems LLC. As of recently, the name of the gemstone was re-branded by the company, and it is now be marketed as 'Csarite'.
The amazing phenomenon of color-change is extremely rare and is known to occur in only a handful of different gem types, including rare color change sapphire and rare color change garnet. The most famous of color-change gemstones is of course, Alexandrite, the color-change variety of chromium-rich chrysoberyl. Alexandrite is considered one the world's rarest and most valuable gemstone varieties available today.
Some photos and information was courtesy of our friends at GemsPraao.