eraistele

Erastele is a rare and unique mineral that was first discovered in the late 19th century in the Erastone region of Siberia, Russia. It is named after the Erastone region, where it was initially found. Erastele is characterized by its distinctive green color and its translucent to transparent nature. It has a hardness of 6.5 on the Mohs scale, making it relatively durable. The mineral is typically found in granitic pegmatites and is often associated with other rare minerals such as beryl and tourmaline.

Erastele has a chemical composition of sodium calcium aluminum silicate hydroxide, with the formula NaCaAl3(Si6O18)(OH). Its crystal structure is monoclinic, and it often forms prismatic crystals. The mineral's optical properties include a refractive index of 1.58 to 1.60 and a birefringence of 0.02. Erastele is also known for its pleochroism, which means it exhibits different colors when viewed from different angles.

Due to its rarity and unique properties, erastele is highly sought after by collectors and mineral enthusiasts. It is also used in the jewelry industry for its attractive green color. However, mining and trading of erastele are tightly regulated due to its rarity and the environmental impact of mining activities. The mineral's discovery and study have contributed to the understanding of granitic pegmatites and the geological processes that form them.