Chrysocolla with cuprite is shown in the front surrounded by Turquoise-like Chrysocolla cabs.
Chrysocolla is quite abundant and widespread in Michigan’s copper country. I have found some wonderful specimens while hunting copper on the old spoil piles. Some of my best finds are copper-included chrysocolla. These copper inclusions involve large areas of native copper and not merely specks which I have observed in Arizona material.
Chrysocolla is always associated with hydrothermal copper deposits. Beautiful examples have been found at the copper mines in Arizona and other locations, but here I will talk about Michigan Chrysocolla.
Sometimes the Chrysocolla is so nice in the Upper Peninsula that you would swear it was Turquoise. Other times this U.P. gemstone is beautiful blue as it combines with malachite. Michigan chrysocolla is sometimes referred to as “U.P. Turquoise” when found in a high quality. I have friends in the U.P. that would swear in court this material IS Turquoise and not chrysocolla.
The very best chrysocolla I’ve found in the Keweenaw Peninsula is blue and combined with clear silica. According to the book Minerology of Michigan by E.W. Heinrich and revised and edited by my friend George W. Robinson there has been no Turquoise located in Michigan. This book is my rock bible when it comes to Michigan minerals, and I highly recommend it to anyone that hunts rocks and minerals in Michigan
Chrysocolla is a hydrous copper aluminum SILICATE whereas Turquoise is a hydrous copper aluminum PHOSPHATE. Chrysocolla is a harder material than it’s relative Turquoise, simply because of the silica content. Chrysocolla requires no stabilization, as is often the case with the softer Turquoise.
A typical piece of Chrysocolla from the Bumbletown location.
When I find Chrysocolla I can sometimes find associated minerals such as cuprite, malachite, limonite, and native copper in the same area. One of the mines rich with Chrysocolla is the Bumbletown (Bumblebee Mine). You can load up with ornamental rock if you want to carry it home. The green Chrysocolla fills the space between the unusual matrix at this location. I must tell you that 15 years ago this location produced some really excellent Chrysocolla but I think it would take a lot of digging and luck to find the “good stuff” now. If you dig at Bumblebee look also for Datolite. Before hunting any mine dumps in the Keweenaw, check on current ownership. These properties do change hands occasionally. Happy hunting!