A representative example of aragonite from Sterling Hill. Aragonite, a calcium carbonate, is a common mineral species worldwide but uncommonly seen in the Franklin and Sterling Hill zinc mining district. The aragonite from Sterling Hill is world-renowned for its large, radiating clusters of white crystals and has provided many picturesque examples. This specimen would be considered a representative coating or crust among the aragonites of Sterling Hill. The aragonite appears in this specimen as a white, opaque, flat-lying crust. This should not dissuade any collector from obtaining this example. The matrix is composed of grains of dull to metallic black franklinite and brownish, dull-lustered willemite set in a white opaque calcite matrix. Aragonite is the principal member of the Aragonite Group, and aragonite is the second most common polymorph of natural calcium carbonate (the most common is calcite). It is significantly less widespread and abundant than calcite and is formed under a much narrower range of physiochemical conditions. It is metastable relative to calcite and often converts to calcite accompanying changes in the environment. It is nearly always a low-temperature, near-surface mineral. The open pits at Sterling Hill were considered the surface outcroppings of the Mud Zone, a region of deeply altered rock, and were known to go down to just below the 430-foot level in the Sterling Mine. It is from this altered material that the many wonderful clusters of aragonite came from. The aragonite does fluoresce a moderate blue-white under shortwave, willemite a moderate green, and the calcite a dull red under (254nm) ultraviolet light. The specimen sits on one end for a secure, optimal display.
Dimensions are 10.4x13.0x5.5cm - 4¼x5¼x2¼in. Please note the centimeter cube and inch bar for scale.
Weight in grams and ounces: 909.7g - 32.09oz.
From the Sterling mine, Ogdensburg, NJ.
The previous collection this specimen was in is
# is the museum's Collection Sale number previously offered in the museum shop.
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All potential buyers need to be aware that being able to view fluorescent minerals requires an ultraviolet lamp. Most of the minerals from the Franklin and Sterling Hill zinc mining district fluoresce under shortwave ultraviolet light. The shortwave wavelength is 254nm or otherwise known as UV C. Always read the description carefully to determine if the main mineral of interest for a particular specimen will fluoresce. ALL fluorescent minerals depicted in our storefront are illuminated by two (2) 35 watt Triple short/mid/long wave AC 35SML-110/220 Way Too Cool LLC ultraviolet lamps. There are several available brands and models of ultraviolet lights on eBay and other online sources. For further information on ultraviolet light and fluorescent minerals, copy and paste the following and go to >>> geology.com/articles/fluorescent-mineral/.
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DISCLAIMER: Every reasonable effort was made to identify the mineral species noted in each specimen accurately. The occasional label from previous collection(s) may misidentify some species, and the current title and description here reflect the latest mineral species identification. A modest effort was made to depict a fluorescent specimen accurately as possible.
In some cases, overexposure should be expected in select photographs to compensate for a fluorescent specimen's weak response. All buyers should exercise safe viewing practices regarding the use of ultraviolet light. Visual dark adaption is highly recommended in the optimal viewing of fluorescent minerals. Buyers should also be aware of what type of lighting to view the specimens under. This can result in perceived differences of color and contrast due to color and contrast shifting under various kinds of lights available.
All photographs were taken with a Nikon D5300 digital camera with a Nikon DX AF-S 18-55mm lens attached with a UV filter. Lighting was done with a pair of OSRAM 8.5 watt LED A19 5000K 800 lumens bulbs in brushed aluminum reflectors. The photographs were processed on a color-calibrated flat panel monitor. Do note the Imperial measurement conversion is the nearest equivalent to the listed metric measurement.
--- All photographs appearing on this listing or any other Franklin Mineral Museum listing are the property of the Franklin Mineral Museum. Photographs can be used strictly for personal use only. Otherwise, the photographs posted here are protected by U.S. Copyright Laws. They are not to be downloaded or reproduced for public use or distribution in any way without the written permission of the Franklin Mineral Museum.