Oldhamite, sulphide of calcium,
Osbornite, oxy-sulphide of calcium and titanium or zirconium,
Daubréelite, sulphide of iron and chromium,
Lawrencite, protochloride of iron,
Asmanite, a species of silica,
Maskelynite, a singly refracting mineral with the composition of labradorite.
Weinbergerite, silicate intermediate in chemical composition between pyroxene and nepheline.
Nature of troilite, asmanite and maskelynite.
Of the above, Troilite is perhaps identical with some varieties of terrestrial pyrrhotite: Asmanite, the form of silica obtained in 1867 by Prof. Maskelyne from the Breitenbach meteorite, was announced by him in 1869 to be optically biaxal, and thus to belong to a crystalline system different from the hexagonal to which both tridymite, then just announced by Vom Rath, and quartz had been assigned. Later investigations of tridymite have shown that its optical characters and crystalline form are inconsistent with the hexagonal system of crystallisation, and it is not impossible that asmanite and tridymite may be specifically identical. It has been found that tridymite becomes optically uniaxal at a moderate temperature, and its general characters appear to be essentially identical with those of asmanite. According to one view, Maskelynite is the result of fusion of a plagioclastic felspar; according to another, it is an independent species chemically related to leucite.
Compounds identical with terrestrial minerals.