Jewelry, Gems, & Minerals/Gaspeite



Can you tell if this pendant is Gaspeite or green turquoise? Are you able to approx its value? Weight 5oz, 1 5/8" X 1 1/4" and about 1/4" thick.

Giving a good assessment of the mineral species from pictures is always problematic. At first glance it looks indeed like green turquoise (CuAl6(PO4)4(OH)8����O), but other viable options would be gaspeite ((Ni,Fe,Mg)CO3), malachite (Cu2CO3(OH)2), or jadeite ( NaAlSi2O6). If your piece does not have a protective coating, like lacquer, you could do a simple acid test. This might damage your stone slightly, however, so I would do this on the back side and rinse off immediately with soap and water after the test. Place ONE drop of acid, such as strong vinegar or better yet, muratic acid tile cleaner on the sample. You may want to use a light and magnifying glass to observe the reaction. Malachite will effervesce (fizz) vigorously, and gaspeite slightly, because both are carbonate minerals. If the magnesium content in gaspeite is very high, the effervescence will be much subdued and difficult to see unless you have some strong acid. Turquoise or jadeite will NOT fizz, period. Gaspeite is also a fairly soft stone with a Mohs hardness of 4.5 to 5. Again, this test may be damaging to your specimen, so take care. Get a good steel nail, use an inconspicuous place on the mineral and try to scratch it by pushing the nail hard against the mineral and moving it a SHORT distance. If you see a scratch, your stone is most likely gaspeite. If NO scratch ensues, turquoise is a good candidate with a hardness of 5 - 7. However, there is some soft turquoise (Hardness 5) that will be scratched by the nail. There are other non-destructive tests possible, such as specific gravity, but for many of those you will have to remove the stone from the pendant.
If you live close to college or university, you may ask if their earth science department has access to a portable XRF (x-ray fluorescence) unit. If yes, you may arrange to bring your pendant and have them run a quick scan with the instrument. This is totally non-destructive and takes only a minute. If Copper (Cu) and Aluminium (Al)shows up in the analysis, then your stone is a turquoise. However, if Nickel (Ni) is present, then you have a gaspeite.
As far as the value is concerned you will have to ask a bonefide jeweler, since this is outside my area of expertise.

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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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