It's Earth Day, and the greenest thing on my list of things to blog about is chrysocolla (even though it's mostly blue).
This gorgeous gem is a hydrated copper silicate. It forms near copper ore which is why this unusual specimen was found, more ore less, in my back yard of Bisbee, Arizona:
It forms often as small stalactites or a thin and unstable crust on the surfaces of rocks:
Other copper bearing minerals also occur alongside chrysocolla: malachite, cuprite, and azurite. Quartz occurrences are as ubiquitous as always. Fine specimens of chrysocolla in chalcedony are called gem silica:
And the occasional druzy happens:
Plain chrysocolla is a soft stone at 2.5-3.5 on the Moh's scale. This makes it unsuitable for rings and rough wear. Chrysocolla occuring in chalcedony is suitable for anything you might like to use quartz for.