Patriotic Colorado

Last night our GIA Alumni Association of Colorado got to visit the Colorado School of Mines Geology Museum. It’s the second most visited university museum in the country full of amazing gems and mineral specimens.

I learned something new last night. Colorado is the only state in the union that has red, white and blue for it’s state mineral, rock and gem.

Rhodochrosite Crystal from ColoradoI’ve mentioned before in my blog that Rhodochrosite is our Colorado state mineral. This amazing rhodochrosite crystal specimen comes from the famed Sweet Home Mine in the Alma District of Colorado. It’s beautifully red, but it’s very delicate rating only 3.5-4.5 with poor toughness. So Rhodochrosite is not very appropriate for gemstone jewelry. Rhodochrosite comes in many forms, I wrote all about it last year at this time. Put Rhodochroiste in the search bar to the right to learn more.

White Marble from ColoradoMarble is the Colorado state rock! It comes from Marble, Colorado, a small town in Gunnison County Colorado that was first incorporated in 1899.

The white marble from Colorado is said to be of exceptional quality. It was used for the Tomb of the Unknowns at Arlington National Cemetery and parts of the Lincolin Memorial in Washington D. C.

Aquamarine from Mt. Antero ColoradoAquamarine is Colorado’s state gemstone and the birthstone for the month of March. It can be very valuable. The specimen here is from one of the most valuable pockets ever found on Mt. Antero in Chaffee County. Mount Antero has one of the highest concentrations of aquamarine in the country.

As you can see here, aquamarine makes a beautiful mineral specimen, but it is also commonly used for jewelry. Aquamarine rates 7.5 – 8 on the moh’s scale of hardness, so one must be careful when using aquamarine for pieces of jewelry meant for every day wear, such as an engagement ring. Aquamarine is most ideal for necklaces, pendants and earrings.

Interestingly enough, aquamarine is the same mineral species, Beryl, as emerald, yet there are no emeralds in Colorado…at least not that I know of.

In my next few posts I’ll talk about other Colorado gems and minerals.

Author: Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites and

About mrahm

Michelle holds a Graduate Gemologist Diploma, Graduate Diamonds Diploma and Graduate Colored Stones Diploma through the Gemological Institute of America's distance education program. Michelle currently serves as President of the Mile High GIA Alumni Association. She also serves on the board of the Rocky Mountain Jeweler's Association and is a member of the American Gem Trade Association.
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