Sphalerite and Hydrozincite, Big Cottonwood Canyon, Utah

This triangular-shaped piece of waste rock was surface collected from a tailings pile at the Maxfield mine, in Big Cottonwood Canyon, Salt Lake County, Utah. It contains grains of sphalerite that fluoresce bright orange under UV, most brightly under long wave. The spalerite is also phosphorescent and triboluminescent. One side of this specimen is coated with hydrozincite, which fluoresces blue/white under short wave UV. Best viewed under full-wave UV lighting (SW + MW + LW) this piece shows a spectacular two-color fluorescent response. The size of this specimen is 61 x 49 x 24 mm, and it weighs 84 grams.

Located in the Wasatch Mountains above the Salt Lake Valley, the Maxfield mine is a former copper, gold, lead, silver, zinc mine that operated during the early 1900s.

Photograph taken under full-wave UV (short wave + mid wave + long wave) showing the orange fluorescent sphalerite and blue/white hydrozincite.

Photographs taken under visible light (upper left), short wave UV (upper right), long wave UV (lower left), and orange phosphorescence following long wave UV (lower right).

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