The mineral is named after the original collector, Adam Geer, of Utica, New York, US.

This means that the crystal could be inverted and then rotated by 120 degrees to return to its original position.

Geerite is anisotropic which means that it will show interference colors when it is rotated in cross polarized light and that the mineral has different properties in different directions It was first described in 1980 for an occurrence as thin coatings or platelets replacing sphalerite in the type locality in De Kalb Township, Saint Lawrence County, New York.

[3] It occurs associated with spionkopite, sphalerite, tetrahedrite, chalcopyrite, malachite, azurite, brochantite, chrysocolla, cervantite, stibiconite, hemimorphite and calcite in the type locality; and with spionkopite, chalcopyrite, cobaltian pentlandite, magnetite, chromite, andradite, chlorite, diopside in the Eretria deposit.

[3] It has also been reported from a variety of locations worldwide, including the Logatchev-1 hydrothermal field along the Mid-Atlantic Ridge complex.