This rock comes from a location in eastern Siberia known for the incredible blue color. The rock is a skarn, the term for a type of metamorphic rock commonly found when a magma chamber forms next to a limestone deposit. The edge of the limestone is heated, recrystallized, and often altered chemically by fluids coming off the magma.
These fascinating rocks are about 700 million years old. The blue color is created by a unique type of the mineral pyroxene. Diopside is a pyroxene made of calcium, magnesium, and silicon – diopside commonly forms in skarns because the mineral dolomite can supply the calcium and magnesium while the igneous rock will supply silicon.
The blue color in this case reportedly comes from a small amount of the element manganese in the mineral structure. Elements like manganese – transition metals, found in the middle of the periodic table, often contribute strong colors when they’re present because the electrons interact strongly with visible light. That’s why iron gives a strong red color to rust and why manganese gives this pyroxene, called violane, such a lovely blue color. Blue pyroxenes can also be produced by chromium getting stuck in the mineral, similar to how the manganese behaves in this case.
This sample is 32 millimeters across at its widest point.
Thanks so much to everyone who came out to VanCAF! We all had a blast and I can’t wait for the next one!
If you remember, I made this big list to roll random art ideas on. I’ve enjoyed it so much I’m going to keep using it for warmups and weekend doodles. I’m calling them Random Art Encounters. Here’s three more I did at VanCAF.