Translucent lemon yellow fluorapatite crystals from Cerro del Mercado, Durango, Mexico. Calcite, hyalite opal, and quartz form the matrix. The apatite fluoresces a nice peach color under shortwave UV, and shifts to a brighter violet/peach under midwave. The green fluorescence is thought to be hyalite, but could also be chalcedony.
These are found in veins containing gemmy, lemon yellow to greenish fluorapatite crystals cutting through hematite. The crystals form hexagonal shapes with off-center terminations. They are found in vugs, often associated with quartz and calcite. Most crystals are around an inch in length, though larger crystals up to about 4 inches long have been found.