Name:

cryptomelane

A photo of the mineral cryptomelane

Class:

Oxide/Hydroxides

Chemistry:

KMn8O16 potassium manganese oxide

Color(s):

steel gray to bluish black, sometimes dull gray or sub-metallic

Hardness:

6 - 6.5

SpecGrav:

4.36

Fracture:

conchoidal

Cleavage:

unknown

Crystal:

Monoclinic, pseudo tetragonal, often botryoidal, fine grained or fibrous.

Envronment:

secondary mineral in manganese ore deposits

Association:

pyrolusite, manganite

Locals:

| N.C., Arkansas, Arizona, Montana, USA | S. Africa | Ghana | Brazil | Australia |

Misc:

Part of a series of minerals with the general formula AB8O16 where the A represents, Ba, K, Na, Pb, Sr, Y, and the B is taken from the list, Cr, Fe, Mg, Mn, Ti, and V. The minerals include, Coronadite, Priderite, Hollandite, Manjiroite, Mannardite, and Redledgeite.

Photos
& Locals:

1.) Mina Garais, Brazil
2.) Mina Garais, Brazil
3.) Mina Garais, Brazil

4.) Reaphook Hill, Flinders Ridge, Austrailia
5.) Reaphook Hill, Flinders Ridge, Austrailia

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