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Jewelry, Gems, & Minerals/Gaspeite in Colorado?


Gaspeite ?
Gaspeite ?  
On a recent trip to the Arkansas River valley in central Colorado, I found this green rock. The rock is approximately 4 inches across. I broke off a piece and cut and polished it. It takes a very good polish. It does scratch with hard steel(engraver). I haven't found any reference to gaspeite being in Colorado, but sure looks like it to me. What do you think or any other tests I can make to be sure.  Thanks for any help.   Chris

Mineral identification from pictures is always a bit tricky. You sample is mostly NOT Gaspeite. One quick test would be to use a small amount of undiluted full strength muriatic acid (Tile cleaner acid; Lowes, Home Depot, etc.) on the green part of your sample (one drop or two). Since gaspeite is a carbonate nickle ore it would start to effervesce (fizz) when strong hydrochloric acid (muriatic acid) is applied. The reaction would be slight if lots of  Magnesium (Mg)is present and would be more intense with depleting Mg content in the mineral. Make sure you rinse / wash your sample after the test.

Other possible minerals hat would NOT react with acid: Epidote, which is common in that area but usually would be a darker green. Amazonite (Microcline) feldspar which is common around the Pikes Peak region of Colorado, but is often much more blue in color. Both of these could be scratched with a hard steel engraver. Beryl, which is also common in the area and would have the correct color would be difficult to be scratched with a hardened engraver though. Another possibility would be a inosilicate or chain silicate such as an amphibole (hornblende, jade) or pyroxene (diopside, spodumene). The later would be a long shot however.

If you really want to know you could take advantage of our free mineral id services, something we do as part of Metropolitan State University of Denver public outreach. Go to for details.  

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Uwe Richard Kackstaetter, Ph.D. (Dr.K)


I can answer questions concerning minerals, mineralogy, gems, metals, and anything that has to do with geology. However, I am NOT a jeweler. Questions about values, settings, gem stone cuts and appraisals are best directed to other experts on this site. I can however aide in the identification of unknown mineral materials. As a public service and part as training for new geoscientists, our university department provides FREE mineral identification for individuals. Please contact me for details or go to for details..


I am a professor of applied geology and mineralogy with many hours of field experience. Furthermore, I enjoy recreational gold prospecting and mineral collecting. As a professor I am engaged in research concerning minerals and their occurrence.

Member of the GPAA (Gold Prospectors Association of America) as well as the Association of Environmental Geochemists. Member of the GSA (Geologic Society of America) Member of the AIPG (American Institute of Professional Geologists)

Here is a small sampling: Mineral-rock handbook: Rapid-easy mineral-rock determination : written for anyone interested in minerals and rocks - Proctor, Peterson, and Kackstaetter;Macmillan Pub. Co. (New York and Toronto and New York) Physical Geology Laboratory e-Manual [CD-ROM], Kackstaetter, Earth Science Education LLC Colorado Front Range Self-guided Geology Field Trips, Kackstaetter,

Ph.D. in Applied Geology and Mineralogy. I am actively teaching courses in mineralogy and a variety of field courses with mineral collecting opportunities. Background in precious metal exploration.

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