1) Manganese mineral
Found on
https://www.crosswordclues.com/clue/cryptomelane
Cryptomelane is a potassium manganese oxide mineral with formula K(Mn4+,Mn2+)8O16. In 1942 the name cryptomelane was proposed as part of an effort to sort out the manganese oxide minerals referred to as psilomelane. Cryptomelane was identified and defined based on X-ray diffraction studies of samples from Tombstone, Arizona; Deming, New Mexico; Me...
Found on
http://en.wikipedia.org/wiki/Cryptomelane
No exact match found.
