Best viewed using Adobe Flash Player (8 or higher).
Download hereGENERAL DESCRIPTION
Known since the bronze age (approximately -4000 to -1000 years BC), cassiterite is a tin oxide. It is the most important (and about only) tin ore.
It is mined for the manufacture of bronze alloy, in which it is combined with copper. The crystals are generally prismatic and of small size. They are of yellow colour with black, have a characteristic hard luster. Twins, named " elbow twin " are rather frequent.
Cassiterite is found in the hydrothermal veins of average- to high temperature and in the granitic pegmatites. Because of its chemical resistance and its raised hardness, cassiterite frequently concentrates in alluvial deposits, known as "placers".
Its principal deposits are: Johanngeorgenstad in Germany, Horni Slavkov in the Czech Republic and Xue Bao Ding in the province of Sichuan in China. The most beautiful crystals come from the mines of Potosi and Oruro in Bolivia.
In France, cassiterite was mined as tin ore in the granites of Echassières (Allier), Montebras (Creuse), La Villeder and Abbaretz (Morbihan) and St Renan (Finistere). The most beautiful crystals collected in France come from La Villeder where cassiterite is associated to beryl.
The type is not definable because this species was already known before the conditions of deposit of the types were defined.
HISTORY : Name inspired from the Greek word "kασσιτερος" [kassiteros] meaning tin
Species first described in 1832 by François-Sulpice Beudant (1787-1850), French mineralogist
Type-locality: undefined because species already known from the Ancients
ANCIENT NAME : Mine d’étain colorée, étain oxydé
CHEMICAL FORMULA : Sn O2
CRYSTAL SYSTEM : Tetragonal
COLOR : Black
DIAPHANIETY : Transparent
LUSTER : Adamantine
STREAK : White, pale gray
MORPHOLOGIE : Prismatic crystals with pyramidal termination, botryoidal masses
HARDNESS : 6,0-7,0
CHEMICAL CLASS: 6,993
DENSITY : IV - Oxides and hydroxides
GROUP : Rutile
STRUNZ CLASS BEFORE 2001 : 4/D.02-40
STRUNZ CLASS AFTER 2001 : 4.DB.05
