Minerals described in 2000

Biehlite is an exceptionally rare mineral, an antimony arsenic bearing molybdate with formula . It comes from Tsumeb.

Gottlobite, ), is a mineral in the adelite group found as isolated crystals or isometric grains of orange or orange-brown color. The size of the crystals are a half millimeter in diameter and are part of the orthorhombic crystal system. Gottlobite is the vanadate end member in a solid solution formed with adelite (). Gottlobite is also part of the vanadates and arsenates group. With these characteristics, it is similar to the minerals tangeite and austinite by X-ray diffraction methods.

Serrabrancaite is a mineral with the chemical formula MnPO4•H2O and which is named for the locality where it was found, the Alto Serra Branca Pegmatite. The Alto Serra Branca mine has been in operation since the 1940s. It is located in Paraiba, Brazil near a village named Pedra Lavrada. Tantalite is the main mineral mined here. Specimens of serrabrancaite are kept in the Mineralogical Collections of both the Bergakademie Freiberg, Germany and the Martin-Luther Universität Halle, Institut für Geologische Wissenschaften.

Arakiite (IMA symbol: Ark) is a rare mineral with the formula (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As3+O3)(As5+O4)2(OH)23. It is both arsenate and arsenite mineral, a combination that is rare in the world of minerals. Arakiite is stoichiometrically similar to hematolite. It is one of many rare minerals coming from the famous Långban manganese skarn deposit in Sweden. Other minerals bearing both arsenite and zinc include kraisslite and mcgovernite.

Tumchaite, , is a colorless to white monoclinic phyllosilicate mineral. It is associated with calcite, dolomite, and pyrite in the late dolomite-calcite carbonatites. It can be transparent to translucent; has a vitreous luster; and has perfect cleavage on {100}. Its hardness is 4.5, between fluorite and apatite. Tumchaite is isotypic with penkvilksite. The structure of the mineral is identified by silicate sheets parallel {100}, formed by alternation of clockwise and counterclockwise growing spiral chains of corner-sharing tetrahedra. Tumchaite is named for the river Tumcha near Vuoriyarvi mas