The chief natural compounds of aluminium are four in number: oxide, hydroxide (hydrated oxide), silicate and fluoride.
Finally, then, both experiment and the natural occurrence in rocks and meteorites suggest that diamond may crystallize not only from iron but also from a basic silicate magma, possibly from various rocks consisting of basic silicates.
Calcium silicate is also present in the minerals: olivine, pyroxenes, amphiboles, epidote, felspars, zeolites, scapolites (qq.v.).
The alum schists employed in the manufacture of alum are mixtures of iron pyrites, aluminium silicate and various bituminous substances, and are found in upper Bavaria, Bohemia, Belgium and Scotland.
Blocks and logs of agate, chalcedony, jasper, opal and other silicate deposits lie in hundreds over an area of 60 sq.
The duty of the limestone (CaCO 3) is to furnish enough lime to form with the gangue of the ore and the ash of the fuel a lime silicate or slag of such a composition (1) that it will melt at the temperature which it reaches at about level A, of fig.
Here very clean non-magnetic concentrate of willemite, which is an anhydrous zinc silicate and a very highgrade zinc ore, is separated from an intimate mixture of willemite, zincite and franklinites, with calcite and some manganese silicates.
For lager-beer cellars and fermenting rooms, for bacon-curing cellars, and for similar purposes, brick walls with single or double air spaces are used, and sometimes a space filled with silicate cotton or other insulating material.
It has been suggested that ultramarine is a compound of a sodium aluminium silicate and sodium sulphide.
ULTRAMARINE, a blue pigment, consisting essentially of a double silicate of aluminium and sodium with some sulphides or sulphates, and occurring in nature as a proximate component of lapis lazuli.