Euclase

Euclase is a rare occurring mineral from the mineral class of island silicates ( nesosilicates ). It crystallizes in the monoclinic crystal system with the chemical composition BeAl [ OH | SiO4 ] and usually develops short to long prismatic crystals, but also, radial or granular aggregates, which may be colored either colorless or blue by foreign admixtures, greenish or yellowish.

Etymology and history

Was first found and described the euclase 1792 by Haiiy, the εὐ -eu - "good" and κλάσις Klasis " Breaking, breaking " named it because of its perfect cleavage after the Greek words.

Classification

In the old classification of minerals (8th Edition) by Strunz the euclase in the department of the island silicates is sorted with tetrahedral foreign anions ( Neso - Subsilikate ). Since the 9 th edition of this classification, however, the mineral is due to the finer division in the department of " island silicates with additional (O, OH, F, H2O) and cations in tetrahedraler and usually greater coordination ".

The classification of minerals according to Dana assigns the euclase in the department " Nesosilicates Nesosilicate Insular SiO4 Groups and O, OH, F, and H 2 O with cations in and> coordination ", where it forms the euclase group together with Klinoedrit, Hodgkinsonit and Gerstmannit.

Education and Locations

Euclase formed mainly by hydrothermal operations within pegmatites, and quartz greisen.

So far, the mineral was found in the following regions (as of 2009): Luxembourg province in Belgium; Minas Gerais and Rio Grande do Norte in Brazil; Hunan and Jiangxi in the People's Republic of China; Bavaria ( Fichtelgebirge) and Saxony (Vogtland) in Germany; in western Finland; England in the United Kingdom; Trentino -Alto Adige in Italy; Boyacá in Colombia; Zambezia in Mozambique; Erongo in Namibia; Aust- Agder in Norway; Carinthia, Salzburg and Tyrol in Austria; Ancash in Peru; Eastern Siberia in Russia; Ångermanland, Södermanland and Västmanland in Sweden; Ticino in Switzerland; Sabaragamuwa in Sri Lanka; Bohemia and Moravia in the Czech Republic; Zhytomyr Oblast in Ukraine; as well as Alaska, Colorado, Connecticut, Maine, Michigan, New Hampshire, New Mexico, North Carolina, Texas, Virginia and Wisconsin in the United States.

Crystal structure

Euclase crystallizes in the monoclinic crystal system, space group P21 / a with lattice parameters a = 4.780 Å; b = 14.322 Å, c = 4.6335 Å and β = 100.31 °, and four formula units per unit cell.

Use as a gemstone

Euclase is prized as a gemstone with good quality; especially his blue varieties, which are comparable with aquamarine and sapphire. However, due to its perfect cleavage, he is very sensitive to pressure and rapid temperature changes that occur during soldering and touch and can bring the stone may burst.