Esperite and Hardystonite
White or dirty white in daylight, esperite exhibits a brilliant yellow fluorescence under SW ultraviolet light, duller yellow under LW ultraviolet. Esperite was also known as calcium larsenite. It occurs with willemite, hardystonite, franklinite and clinohedrite. For many years the only known occurrence was from the Parker Shaft in Franklin, New Jersey. However, microcrystals were recently reported found at El Dragon mine in Potosi', Bolivia.
- White, gray-white or tan in daylight, hardystonite exhibits a violet-blue fluorescence under SW ultraviolet light, none under LW. The only known occurrence is at Franklin, New Jersey. Crystals are rare. Hardystonite is almost always accompanied by orange fluorescing clinohedrite.
If you like big pictures, here's a 1024x707 JPEG image (69 KB) of the Esperite and Hardystonite.
If you like really big pictures, here's a 1400x963 JPEG image (110 KB) of the Esperite and Hardystonite.
Rocks from Ken Colosky's Fluorescent Collection
Index of Specimen Images
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