I give this name to a substance which may be regarded as of the nature of a hydrated magnesian felspar.

It was found by Mr. Dudgeon and myself in granular limestone, about one third of a mile above and north-east of the hamlet of Balvraid; this hamlet is situated six miles up the Glen Beg of Glen Elg, Inverness-shire.

Only a single large mass containing the mineral was found. In this mass it was associated with blue necronite (orthoclase of limestones), Biotite, and a hydrated labradorite.

Its colour is purplish brown of a pale cast; its structure is crystalline granular, it may be called saccharoid; its hardness is 6; its specific gravity from 2·905 to 2·908