Monday, September 17, 2007

African fine color change alexandrite

An unusual combination of a fine color change, exceptional clarity, and excellent cutting make this stone is one of the very top alexandrites ever to be unearthed from this deposit in Tunduru.

The Tunduru area in southern Tanzania, near the Mozambique border produced a large quantity of sapphires, spinels and chrysoberyls in 1993. All of the easily accessible areas were mined out in one year. Today, mechanized mining is still producing limited quantities of material, but work is difficult in such a remote area. The Tunduru region has produced a variety of outstanding stones including a large clean top color 40ct+ rough diamond and some stunning alexandrite and vanadium colored chrysoberyls

Friday, September 14, 2007

How can I spot the difference between a natural and a synthetic alexandrite?

Natural alexandrites are available in a complete range of colors from brownish to bluish green in daylight to pink, purple, red or brownish red under incandescent light. Compared to natural gemstones, most synthetic alexandrites are somewhat more blue under fluorescent light and strongly red under incandescent light. Large clean and inexpensive stones offered as natural alexandrites are most probably synthetic or not alexandrite at all.

Gemologists study the inclusions to distinguish between natural and synthetic alexandrite. Synthetic stones may also have a lower refractive index and show more fluorescence than natural stones. Natural alexandrites should be purchased from reputable dealers and expensive stones should also be tested and certified by a well established gem lab.