Rhodochrosite ps. Calcite on Galena
Rhodochrosite
– MnCO3
Fluorite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Calcite
– CaCO3
Calcite
Talc (1)Diamond (10)
A copper coin can scratch it.
Did you know?
Rhodochrosite is nicknamed Inca rose, its banded pink finest in old Andean mines once worked for silver.
Look through a clear rhomb of Iceland spar calcite and the world doubles, split into twin images by the crystal's double refraction. Some researchers think Norse sailors used this very effect to find the sun through cloud, the so-called sunstone, though the idea remains a debated hypothesis.
Galena was the heart of the first crystal radios. Acting as a natural semiconductor, it let a fine wire called the cat's whisker pull voices from the air with no battery at all.
