Oxide minerals and their features

The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys 

Hematite

Chemical formula : Fe2O3 

Mohs Scale : 5.5 - 6.5

Crystal System : Trigonal

Melting Point : 1538 C

Diaspore

Chemical formula :  AlO(OH) 

Mohs Scale : 6.5 - 7

Crystal System : Orthorhombic

Manganese Dendrites

Black dendritic films of various visually indistinguishable black manganese oxides, may consist of birnessite, coronadite, cryptomelane, hollandite, romanèchite, todorokite or other species. 

From Kütahya, Türkiye.

Goethite

Chemical formula :  FeO(OH) 

Mohs Scale : 5, 5.5

Crystal System : Orthorhombic

Manganese Dendrites

Wulfenite

Chemical formula : PbMoO4 

Mohs Scale : 3

Crystal System : Tetragonal

From Mexico

Hematite

Manganese Dendrites

From Kütahya, Türkiye