known as a pale-yellow, reddish-brown, or black isometric mineral composed of sodium calcium tantalum oxide with a small amount of fluorine.

it is a name of a group of oxide minerals of a similar stoichiometry having tantalum prevailing over titanium and niobium.

The microlite group belongs to a large pyrochlore supergroup that occurs in pegmatites and constitutes an ore of tantalum.

Association minerals include: albite, lepidolite, topaz, beryl, tourmaline, spessartine, tantalite and fluorite.

Another occurrence of microlite is the Clark Ledges pegmatite, Chesterfield, Hampshire County, Massachusetts.