About the collection

Cryptomelane

A tetragonal crystal of  oxide mineral , with a peculiar bulbous shape and gray-black color  .On a Mohs scale , which measures hardness of a mineral , cryptomelane comes up to 6- 6.5 units.

As a mineral it’s quite brittle, though cryptomelane is very popular with jewelers  and amateur gem collectors . The reason for this is the crystal’s characteristic metallic sheen that can be achieved through polishing it, as it can take on a glaze, the crystal can also be of an opaque dull matte . The name itself derive from Greek origins, with “ crypto” meaning hidden, uncovered  and “melano” defined as dark, black.

The mineral is a monoclinic crystal,with an unstable chemical composition of mainly manganese(62%),with potassium, zinc, cobalt ,nickel, barium and sodium elements. Externally , as mentioned cryptomelane has specific structure of bubbly, bulbous shapes .

The oxidized mineral the museum exhibits is 20 cm in length with circumference of 42 cm.  Its an eye- catching piece with its characteristic metallic glow  .

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