Bromellite

Bromellite is a very rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the hexagonal crystal system with the chemical composition of BeO, is so chemically seen a beryllium oxide, and usually develops only small, colorless or white crystals in the millimeter range.

Special Features

Bromellite is pyroelectric, so charges electrically at at intervals varying temperature. Upon irradiation with long-wave or short-wave UV light shows yellow-white fluorescence.

Etymology and history

Was first found Bromellite 1925 in the Swedish mining community Långban and described by Gregori Aminoff, of the mineral in honor of the Swedish physician and mineralogist Magnus von Bromell ( 1679-1731 ) and named after this.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of the Bromellite belongs to the department of " oxides with the molar ratio of metal: oxygen = 2:1 and 1:1 ." The new Strunz'sche Mineral classification divided here but now more specific on the size of the cations involved and the mineral is in accordance with the subdivision " cation: anion ( M, O ) = 1:1 ( and to 1:1.25 ); with only small to medium-sized cations ".

The commonly used in English-speaking classification of minerals according to Dana assigns the Bromellite also in the class of oxides, but there in the department of "simple oxides with a cation charge of 2 ( AO) ".

Education and Locations

Bromellite formed by hydrothermal processes in calcite veins in hematite skarn and limestone skarnisiertem in Natrolith Druze, hydrothermally formed metal nepheline syenite and in pegmatites. Accompanying minerals include Chamosite, diaspore, Manganophyllit, Natrolite, richterite and Swedenborgit.

So far, the mineral world could only nine localities (as of 2009) are recorded: In the " Bollinger's Mine" at Torrington (New South Wales) in Australia; in the Xianghualing mine in the district Linwu (Hunan Province) in China; in the mine " Costa Bonne " in Prats -de- Mollo -la- Preste in France; at Sagåsen in the Norwegian county of Telemark; Pitkyaranta, Kola and Yekaterinburg in Russia; as well as its type locality Långban and Pajsberg in Sweden.

Morphology

The crystals of Bromellite are usually well developed and of a prismatic habit, stretched and unilaterally ( hemimorphic ) pyramidal statements. Also tabular crystals parallel to {0001 } and rosette-shaped mineral aggregates are possible.

Crystal structure

Bromellite crystallizes isotypic with zincite in the hexagonal crystal system in space group P63mc with the lattice parameters a = 2.698 Å and c = 4.380 Å and two formula units per unit cell.

Use

Bromellite is a good conductor of heat and is used among other things in thermocouple protection tubes, crucibles, spark plugs and electronics as a heat sink for semiconductor devices as well as in reactor technology.

Precautions

Bromellite is not suitable as a highly toxic compound for a private mineral collection.