Willemite, Calcite - image 1

Willemite, Calcite

G

George & Deborah Polman

0 for sale

Willemite (green) and calcite (red), under shortwave ultraviolet light, 17.8 cm, from the Sterling Hill mine, Ogdensburg, New Jersey.

Product details

Species

Willemite, CalciteAbout Willemite →

SizeLarge Cabinet

Dimensions17.8 cm

Added on02/13/2026

Locality

USA, New Jersey, Sterling Hill MineRegional guide →

Publications

Mineralogical Record Mineral Collections In Arizona page 142

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Willemite

Learn about Willemite

fluorescent zinc silicate with UV glow; daylight colors range from colorless to pistachio, iconic from Franklin–Sterling Hill and Tsumeb.

Willemite

Willemite from Sterling Hill Mine, New Jersey, USA

Sterling Hill willemite is one of the classic collector materials of American mineralogy: a zinc silicate, Zn2SiO4, that can look modest in daylight and then turn electric green under ultraviolet light. In the best pieces, tan to reddish-brown willemite crystals sit in white calcite with black franklinite and, less commonly, red zincite—an ore assemblage so distinctive that even small fragments announce the Franklin-Ogdensburg district at a glance. The daylight palette is earthy and old-mine: mahogany, brick red, honey brown, buff, white, and black. Under shortwave UV, however, willemite becomes the bright green signal in the rock, while calcite may burn red to orange-red and franklinite stays dark.