Color Change Garnet from Bekily, Madagascar

Color Change Garnet, Bekily, Madagascar
Color Change Garnet
Bekily, Madagascar

The gem world has long believed that garnets occur in every color of the spectrum, except for blue. But we had to abandon that belief when blue color-change garnets were first discovered in the Bekily district in southern Madagascar in 1998. 

These unusual garnets are actually a teal blue or greenish-blue under daylight or fluorescent light, changing to reddish-purple under incandescent light. The color change is quite pronounced and these rare garnets have become sought after by collectors.

Color change garnets are typically mixtures of pyrope and spessartite, sometimes with minor percentages of almandine and grossular. The color change is due to trace amounts of vanadium and/or chromium. 

There are actually two different colors of color change garnets found in the Bekily deposit in Madagascar. One variety is greenish-yellow to yellowish-green in daylight and an intense pink to red under incandescent light. The other variety is bluish-green to greenish-blue in daylight with a strong change to intense purple or purplish-red under incandescent light. The differences are due in part to varying concentrations of vanadium and chromium. The blue-green to purple color change garnets have relatively high concentrations of vanadium and low concentrations of chromium. 

A distinguishing characteristic of the Bekily color-change garnets are 4 sets of fine rutile needles, with each set at a 70 degree angle from the others. These needles are best seen under microscopic examination, but can sometimes be seen at lower magnification under high illumination.

10.31 ct Color Change Garnet, Madagascar
10.31 ct
Color Change Garnet

Bekily, Madagascar

Color change garnets have also been found in east Africa (Tanzania and Kenya) and Sri Lanka. But the Madagascar deposit has attracted special attention for the unique blue stones and the strong color change. In addition, while most color change garnets are found only in smaller sizes (under 2 carats), the Bekily deposit has produced a number of valuable larger stones.

We recently acquired a parcel of high quality rough from the Bekily mine and we have cut a number of fine gems from it, including several pieces over 3 carats. But the largest stone from this parcel yielded an extaordinary 10.31 ct square cushion with a distinct color change from bluish-violet to reddish-purple.

See our collection of Rare Color Change Garnet

 

 
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