.60" Vibrant Blue Kröhnkite Specimen - Chile

About Kröhnkite

Kröhnkite is a rare copper sulfate mineral named after B. Kröhnke who first researched it. Often is will display a blue or green coloration, however it can also be found as dark sky blue, greenish blue, and yellowish green. Kröhnkite may be replaced by saranchinaite, the anhydrous form of the mineral, if heated to temperatures above 200 °C (392 °F). It has the same general formula as minerals which are found in environments affected by hydrothermal alteration, making it important in identifying where such alterations have occurred. Furthermore, the minerals sharing this composition are organized according to three crystal structure types, one being the unique kröhnkite structure which is often used to describe minerals exhibiting the same chain-like structure.

General Chemical Formula - Na2Cu(SO4)2•2H2O