SG Heritage Dictionary

Magnesite [Noun] Webster's Dictionary 1828

Carbonated magnesia, or magnesia combined with silex. It occurs in amorphous masses, or in masses tuberous and spungiform; its color is yellowish gray, or white with spots, and dendritic delineations of blackish brown.

Magnesite [Noun] Webster's Dictionary 1913

Native magnesium carbonate occurring in white compact or granular masses, and also in rhombohedral crystals.