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Minerals - Cryptomelane | TerraCollect

Mineral - Cryptomelane

CryptomelaneK(Mn⁴⁺₇Mn³⁺)O₁₆

Chemical Properties

Mineral Class

Oxides and Hydrxides

Toxicity

none

Formula

K(Mn⁴⁺₇Mn³⁺)O₁₆

Unit Cell

a=9,96 b=2,87 c=9,71 β=91° Z=1

Physical Properties

Hardness

5 - 6.5

Streak

blackbrownbrown black

Optical Properties

Color

blackbrowngray

Birefringence

Luster

Pitchy,

Resinous,

Earthy

Transparency

opaque

Pleochroism

Geomineralogical Properties

Crystal System

monoclinic

Composition

Elements

Mass

SiO₂

0,58

TiO₂

0,01

MnO₂

83,13

Al₂O₃

0,37

Fe₂O₃

0,46

MnO

2,08

CuO

0,12

Density

Cleavage

nd

Fracture

conchoidal

Tenacity

Brittle

Point Group

Space Group

Habit

dendritic, coarse, spherical, massive, kidney-shaped, stalactitic, grape-shaped

Formation

Sekundär, in der Oxidationszone von Mangan-Lagerstätten

Paragenesis

Twinning

Nach (010) und (001)

Rarity

Common

Synonyms

Cryptomelane

ZnO

5,23

MgO

0,05

CaO

0,27

BaO

0,13

Na₂O

0,44

K₂O

3,51

H₂O

2,57

P₂O₅

0,06

Arizona

Groups and Members

Hollandit-Supergruppe

Coronadit-Gruppe