Emmensite is a mineral that belongs to the group of borosilicates. It is commonly found as a secondary mineral in hydrothermal veins, specifically in association with tin and tungsten deposits. The mineral was first discovered in 1960 at its type locality in the Emmen district of the Netherlands, from which it derived its name.
Physically, emmensite is characterized by its translucent appearance and range of colors, which can include brown, yellow, gray, or even colorless. It typically occurs as prismatic crystals, with a vitreous to resinous luster.
Chemically, emmensite consists primarily of silicon, boron, and oxygen. Its chemical formula is often expressed as (NH4)2(BeSi2O6(OH)2), denoting the presence of ammonium, beryllium, silicon, oxygen, and hydroxide ions. This composition gives the mineral its unique properties.
Emmensite is known for its moderate hardness, falling between 5 and 6 on the Mohs scale. It also exhibits a specific gravity between 2.83 and 2.88. When subjected to ultraviolet light, emmensite can display fluorescence, emitting a yellow to green glow.
Due to its relatively rare occurrence and limited use, emmensite does not hold significant commercial value. Its main significance lies in its status as a collector's mineral, appreciated for its aesthetic qualities and unique crystal habit. Its historical association with the Emmen district further adds to its appeal among mineral enthusiasts and collectors.
