Becquerelite

Becquerelit is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the orthorhombic crystal system with the chemical composition Ca [( UO2) 6 | O4 | (OH ) 6] • 8H2O and usually develops transparent, tabular to prismatic and pseudo-hexagonal crystals, but also granular aggregates and crusts of brown yellow, amber- yellow to lemon yellow and yellow-orange color with yellow stroke color. In the crystal surfaces reveals a diamond - to -fat -like shine.

Special Features

The mineral is classified as highly radioactive due to its uranium content of up to 72 % and has a specific activity of about 129.7 kBq / g (compared to natural potassium 31.2 Bq / g).

Etymology and history

Was first discovered in the Becquerelit " Shinkolobwe Mine" in the province of Haut - Katanga Democratic Republic of Congo and described in 1922 by Alfred Schoep ( 1881-1966 ), of the mineral in honor of the discoverer of radioactivity, Antoine Henri Becquerel ( 1852-1908 ), named.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Becquerelit belonged to the mineral class of " oxides and hydroxides " and then to the Department of " uranyl hydroxides and hydrates ", where he and along with Billietit, Compreignacit, Masuyit Protasit an independent group formed.

The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Becquerelit also included in the category of " oxides and hydroxides " and there in the department of " Uranyl Hydroxide ." This division, however, is further subdivided according to the presence of other cations, as well as the crystal structure, so that the mineral, according to its composition and structure in the sub-department "With additional cations (K, Ca, Ba, Pb, etc.), mainly UO2 (O OH) 5 pentagonal polyhedra " is to find where it is named as the " Becquerelitgruppe "with the system no. Forms 4.GB.10 and the other members Billietit and Protasit.

The classification of minerals according to Dana assigns the Becquerelit in the class of " oxides and hydroxides ", but there in the department of " uranium and thorium oxides " one. He is also named as the " Becquerelitgruppe " with the system no. 05:07:01 and the other members Compreignacit and Billietit to find " uranium and thorium oxides with alkali or hydrated Hydroxidkomponenten " within the subdivision of.

Education and Locations

Becquerelit formed secondarily as a weathering product of uraninite in the oxidized parts of uranium deposits, but rarely in the pegmatites. Accompanying minerals are uraninite addition, you still Schoepit, Soddyit, Curit, Fourmarierit, Dewindtit, Ianthinit, Wölsendorfit, Rutherfordin, Masuyit, Kasolit, Johannit, Uranopilite and Zippeite.

Worldwide, Becquerelit so far (as of 2011) are detected in about 90 localities. Apart from its type locality " Shinkolobwe Mine" was found the mineral in the Democratic Republic of Congo still at Kolwezi in the " Kamoto Principal Mine" and " Musonoi Mine".

In Germany Becquerelit occurred among others in the Clara mine in Baden- Württemberg; at Wölsendorf district Schwandorf in Bavaria; in the uranium deposit of Ellweiler in Rhineland -Palatinate and Johann George Town and Tirpersdorf in Saxony evident. In Austria, the mineral previously could only Mitter mountain in the municipality of Mühlbach (Salzburg ) was detected and found in Switzerland, among others, in several parts of the Trienttals and Isérables in the canton of Valais.

Other localities are Argentina, Australia, China, England ( UK ), France, Italy, Canada, Madagascar, Mexico, New Zealand, Norway, Romania, Russia, South Africa, Czech Republic and the United States of America (USA).

Crystal structure

Becquerelit crystallizes in the orthorhombic space group ( Raumgruppen-Nr. 33) with the lattice parameters a = 13.84 Å; b = 12.38 Å and c = 14.92 Å and four formula units per unit cell.

Security measures

Due to the high radioactivity of the mineral samples should be stored in a dust - and stahlungsdichten containers, especially but never in living, sleeping and working areas. Similarly, inclusion in the body ( incorporation) should be definitely prevented and the safety of direct body contact and worn when handling the mineral mask and gloves.