Transparent Rhodonite with unusual inclusions
Taywiga Phataphol B.Sc., G.G.
Most Rhodonite seen in the trade are translucent to opaque pink, often with black veins or spots. Many are fashioned into beads and cabochons. However, transparent Rhodonite is also found in some localities.
Figure 1: 4.48 ct. transparent orangy red cabochon Rhodonite.
A few years ago, we were asked to identify the 4.48 ct. oval orangy red cabochon. After examining the gemological properties, the results were the followings; RI – 1.72 spot reading, when tested on slightly flat base RI approx. 1.72-1.73 ; S.G. = 3.65 ; inert to long-wave and moderate red to short-wave UV ; orange/pinkish red pleochroism ; biaxial optic character in polariscope ; a band at 530-570 nm and faint line at 503 nm in a desk-model spectroscope. The inclusions were many curved tubes and crystals. In addition, the cleavage was found and hardness of the stone was approximate 5.
Figure 2: Curved tubes inclusions and crystals.
Figure 3: Curved tubes seen under 45X microscope.
Figure 4: Cleavage was observed under reflected light.
The results above indicated that it was Rhodonite. Though, we were unfamiliar with these unusual inclusions in Rhodonite, especially the curved tubes. These tubes looked similar to the tubes seen in some Winza rubies from Tanzania. (See more from lab note at GIA Laboratory Bangkok
Webster R. (1994) Gems: Their sources, descriptions and identification, 5 th ed., p 365.
Pardieu V., Winza Ruby? No sorry. My name is Rhodonite!, http://www.giathai.net.