Willemite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameWillemite
Chemical FormulaZn2SiO4
Mohs Hardness5.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagedistinct on {0001}
Fractureconchoidal
Specific Gravity3.9
Colorswhite, yellow, green, brown, reddish-brown, colorless
Transparencytransparent
Type LocalityFranklin, Franklin Mining District, Sussex County, New Jersey, USA
Mineral GroupSilicates
Useszinc ore, fluorescent mineral specimens, collector
Associated Mineralsfranklinite, zincite, calcite, rhodonite
Rarityuncommon
Description
This image displays a specimen of willemite fluorescing a brilliant neon green under ultraviolet light, highlighting its characteristic phosphorescence. Darker areas within the specimen likely represent non-fluorescent associated minerals.
Geological Context
Willemite typically forms in highly metamorphosed zinc ore deposits, often associated with carbonate rocks. The deposits at Franklin and Sterling Hill, New Jersey, are world-renowned for their unique zinc-manganese mineralogy.
