2" Yellow-Green Fluorapatite Crystals in Calcite - Ontario, Canada

This is a fluorapatite crystal that was collected from Tory Hill in Ontario, Canada, from a digging locality that is now closed.

Fluorapatite is the most common variety in the apatite group. It's known to form early in almost all igneous rock as small, microscopic crystals. It can display a wide variety of colors and can be confused with beryl, phenakite and milarite. Often forming bright, lustrous crystals with hexagonal faces and off-center terminations. They are found in vugs, often associated with quartz and calcite. Most complete crystals are around an inch in length, though larger crystals up to about 4 inches long have been found.

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.
Fluorapatite & Calcite
Bear Lake Diggings, Tory Hill, Ontario, Canada
2" wide specimen