Calcite (Inventory)/Spar/nailhead
From LagWiki
The nailhead field should be used to list stations which exhibit nailhead spar.
Nailhead spar typically is "flatter" or more "cubic" than dogtooth spar. The shape is a rhombohedron where each facet is a rhombus. Except for the shape of each crystal (which is really just one of the two primary crystaline shapes of calcite) it has characteristics very similar to dogtooth spar and can be found in similar locations.
See also
