Willemite with Franklinite - image 1
Willemite with Franklinite - image 2
specimen video

Willemite with Franklinite

$650.00

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Crystal Classics
Crystal ClassicsFeatured
Tucson, Arizona, USA
7,579 for sale·132 sold
Willemite from the world famous Sterling mine at Ogdensburg, New Jersey, USA, is typically found as a massive uncrystallised component in the complex ores found here and at its nearby neighbour, Franklin mine. Franklin and Sterling mines worked the same orebody, but independent of each other at opposite ends of the outcropping syncline. This is a really superb well crystallised example of Willemite, as two near perfect crystals, one large and one much smaller. The former measures 3.0 x 2.3 x 1.8 cm and the latter, 1.7 x 1.2 x 1.2 cm, both are partly embedded in a massive Calcite matrix. Four, part-octahedral Franklinite crystals are clustered between the two Willemites. As one would expect, the specimen fluoresces nicely in both SW and LWUV, the Willemite crystals lime green and the Calcite orange-red. The two wavelengths produce similar fluorescence, although in SW the colours are brighter and a little more vibrant.

Product details

Species
Willemite, Calcite, FrankliniteAbout Willemite →
SizeSmall Cabinet
Dimensions6.8 x 4.5 x 3.8 cm
Listed on10/24/2024
Locality
USA, New Jersey, Sterling Hill MineRegional guide →
SKUCC21644

Learn more

Willemite
Mineral guide
Learn about Willemite
fluorescent zinc silicate with UV glow; daylight colors range from colorless to pistachio, iconic from Franklin–Sterling Hill and Tsumeb.
Willemite
Regional guide
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.