Sinhalite

Sinhalite is a rare mineral commonly found in brown to greenish brown and sometimes greenish-yellow. It was first discovered in Ceylon (now known as Sri Lanka) and was misidentified as a brownish variety of the normally green Peridot. Not until 1952 when an unusually dark specimen of Sinhalite was studied was it identified as a new mineral. Sinhalite gets its name from Sinhala, the Sanskrit name for the island of Ceylon.

Sinhalite is formed from magnesium aluminum borate (MgAlBO4). It ranks 6.5 on the Moh’s Scale of hardness with a Specific Gravity of 3.5 and a Refractive Index of 1.66 to1.71. Sinhalite crystals are vitreous and transparent to translucent. Its crystal habit is limited to alluvial grains found in gem gravels.

Another interesting characteristic of Sinhalite is it strongly pleochroic, meaning that it may appear to have different colors from different viewing angles. Some Sinhalite specimens change color from green to light brown or dark brown.

Sinhalite is normally found as gravel mineral of other gemstones such as Ruby, Sapphire, Peridot and Garnets. Sinhalite’s locality is limited to only a few locations worldwide. It has been found in Balangoda, Sabaragamuwa province, Sri Lanka and Mogok, Sagaing, Myanmar. In Russia it has been found in Aldan Shield, Siberia.

Sinhalite is usually sought after only by collectors of rare and unusual gemstones. Because of its rarity and the not too overwhelming demand for brownish-green gemstones, Sinhalite has not enjoyed much popularity in the international gemstone market. But for mineral collectors Sinhalite is an important addition to a complete mineral collection.