Chrysocolla

Copper can be found in several minerals, such as the Bornite which I recently discussed. Another copper mineral (which I think is prettier than Bornite) is Chrysocolla (pronounced: crĭs - ō - CŌ' - lă). The presence of copper and aluminum is what gives the stone its beautiful blue-green color, whereas the presence of iron in unoxidized bornite gives it a more earthy color.

^{~my chrysocolla specimen, photo by me~}

As can be seen in the chemical formula — (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O — varying amounts of copper and aluminum can make the mineral form slightly differently, giving rise to different hardnesses and physical manifestations. Some of it is too soft to be used as gemstones, but some chrysocolla is harder — it all depends on how much silica is combined into the stone as it forms.

^{~photo from Wikipedia¹~}

Because chrysocolla contains both copper and aluminum as primary ingredients, as does turquoise, the two stones are often confused. To an expert, the differences are usually obvious, but the amateur eye can be easily fooled. Reputable merchants will properly identify the stones, but less-honest merchants have passed chrysocolla as more-expensive turquoise. The photo at right shows a cabuchon of chrysocolla set into the slide of a bolo tie, and I find this particular stone to be remarkably reminiscent of turquoise. The most obvious giveaway is the flecks of grayish-white silicate material.

The reason turquoise is more expensive than chrysocolla is primarily because of its hardness. Chrysocolla that contains more silica as it is forming, as mentioned above, is harder and approaches the hardness of turquoise. Chrysocolla with less silica is somewhat brittle and breaks easily. And, while chrysocolla is a mineral with silica (a mixture of silicon and oxygen) as a secondary ingredient, turquoise has phosphate (a mixture of phosphorus and oxygen) as a secondary ingredient.

^{~holding the stone for size comparison, photo by me~}

I like the color of my chrysocolla specimen, as well as the patterns and lines that appear on the surface of the stone. Gazing at it is similar to "cloud watching," in that different patterns and shapes appear all around the stone.

^{~photo by me~}