Oxides and Hydroxides: Ilmenite

Composition: FeTiO₃; magnesium may substitute for iron

Crystal system: Trigonal; commonly massive or as discrete grains in sands and sandstones

4.8.1
massive ilmenite

Properties:

• Metallic to submetallic lustre
• Black color
• Black streak
• Knife will not scratch or barely scratches (Mohs Hardness 5-6)
• High density
• No cleavage
• Smooth fracture or parting
• Not ferromagnetic; may appear slightly magnetic due to intergrown magnetite
• Does not react with hydrochloric acid (HCl)
  

Occurrence:

Ilmenite occurs as an accessory mineral in igneous and sedimentary rocks, with other oxides in massive segregations in mafic igneous rocks and in heavy mineral sand deposits .

Ilmenite is one of the most important sources of titanium.