ULEXITE
ULEXITE Ulexite – NaCa[B5O6(OH)6].5H2O – is a very rare borate, characteristic of evaporitic parageneses in salt lakes. It is one of the three most important ore minerals of B, along with borax and colemanite. It forms “ulexite-stone”; some occurrences contain more than 1 billion tons of ulexite. It forms pseudomorphs on borax. Under ultraviolet light, […]
URANINITE
URANINITE Uraninite – UO2 – is a common oxide that constitutes the most important ore of U. It is classified in the Uraninite Group, in the Thorianite-Uraninite Series. It may contain a number of impurities such as Th, Pb, Zr, He, Tc, Ra, Po, Fr and Rare Earths (Ac, Ce, Y, Pm, Er and La). […]
ULVÖSPINEL
ULVÖSPINEL Ulvöspinel – TiFeO4 – (formerly known as “ulvite”) is a relatively rare (or rarely recorded!) oxide that occurs in basic rocks, usually forming exsolutions in magnetite. It is present in Fe-Ti ores, but is not the main ore mineral. High contents of ulvöspinel, which is not magnetic, create major problems in the beneficiation of […]
UVAROVITE
UVAROVITE See “Garnet” Uvarovite is a green garnet with Ca and Cr.
ULLMANNITE
ULLMANNITE Ullmannite – NiSbS – is a fairly rare sulfide, typical of Ni-Co-Ag-Bi ores. In these polymetallic ores, it is not so important due to its rarity. It belongs to the Cobaltite Group and forms a series with willyamite – (Co,Ni)SbS. It commonly contains Fe and Co (both replacing Ni), Bi, and As as impurities. […]
UMANGITE
UMANGITE Umangite – Cu3Se2 – is a very rare sulfide. It can constitute Se ore, but Se is normally obtained as a by-product in the refining of Cu, Ni, and Pb ores.It is classified in the Berzelianite-Umangite Group. It may contain Ag. 1. Characteristics Crystal system: Tetragonal scalenohedral. Color: Cherry red to light reddish-violet, fading to […]