heliotrine

Heliotrine is a rare, pink to red, monoclinic mineral with a hardness of 5.5 to 6 on the Mohs scale. It is a lithium aluminum silicate, with the chemical formula LiAlSiO4. Heliotrine is typically found in granitic pegmatites and is often associated with other lithium-bearing minerals such as spodumene and petalite. It was first discovered in 1898 in the Heliotrope mine in the Black Hills of South Dakota, USA, from which it derives its name.

Heliotrine is known for its distinctive pink to red color, which is due to the presence of lithium in its structure. It has a vitreous luster and a conchoidal fracture. The mineral is often found in small, prismatic crystals or in massive aggregates. It is a member of the zeolite group of minerals, which are characterized by their open framework structures that can accommodate various cations.

Heliotrine is not commonly used in jewelry due to its rarity and the fact that it is not as hard as some other gemstones. However, it is sometimes collected by mineral enthusiasts for its unique color and crystal habit. It is also of interest to geologists and mineralogists due to its association with lithium-bearing minerals and its role in the formation of granitic pegmatites.