Fluor-uvite is a

tourmaline Tourmaline ( ) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is a gemstone and can be found in a wide variety of colors. ...

mineral with the chemical formula CaMg₃(Al₅Mg)(Si₆O₁₈)(BO₃)₃(OH)₃F. It is a rare mineral that is found in calcium rich

contact Contact may refer to: Interaction Physical interaction * Contact (geology), a common geological feature * Contact lens or contact, a lens placed on the eye * Contact sport, a sport in which players make contact with other players or objects * ...

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, cau ...

s with increased amounts of boron. Uvite is

trigonal In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crystal ...

hexagonal, which means that it has three equal length axes at 120 degrees, all perpendicular to its fourth axis which has a different length. Uvite is part of the

space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it ...

3m. Uvite's hardness has been measured to be 7.5 on the

Mohs hardness scale The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the ...

. The color of uvite widely varies, depending on the sample, but is mostly deep green or brown. In regard to uvite's optical properties, it is uniaxial (-) and anisotropic, meaning that the velocity of light in the mineral depends on the path that it takes. In plane polarized light, uvite is colorless to pale yellow and shows weak pleochroism. Uvite was first found in 1929 in

Uva Province Uva Province ( si, ඌව පළාත, Uva Paḷāta, ta, ஊவா மாகாணம், Uvā Mākāṇam) is Sri Lanka's second least populated province, with 1,259,880 people, created in 1896. It consists of two districts: Badulla and ...

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

, hence the name. Uvite has no use, but is commonly found in mineral specimen collections. The mineral is sought after by collectors because of its pronounced colors, crystal structure, and often large crystal size.

References

{{reflist Aluminium minerals Calcium minerals Cyclosilicates Magnesium minerals Trigonal minerals Minerals in space group 160 Tourmalines