# Mineral Hardness Color Transparency Crystal System Probability See More
1Ilmenite5.0 - 6.0Iron black or blackOpaqueTrigonal0.011
2Nickelskutterudite5.5 - 6.0Tin white - silver greyOpaqueIsometric0.006
3Tantalite-(Mn)6.0Pink to nearly colourless, reddish brown to blackOpaqueOrthorhombic0.005
4Columbite-(Mn)6.0Black to brownish black, reddish brown in transmitted lightTransparent, Translucent, OpaqueOrthorhombic0.003
5Magnetite5.5 - 6.5Greyish black or iron blackOpaqueIsometric0.003
6Clinohumite6.0Monoclinic0.003
7Turquoise5.0 - 6.0bright blue, sky-blue, pale green, blue-green, turquoise-blue, apple-green, green-grayTransparent, Translucent, OpaqueTriclinic0.003
8Augite5.5 - 6.0Brown-green, black, green-black, brown, purplish brownTranslucent, OpaqueMonoclinic0.003
9Pyrite6.0 - 6.5Pale brass-yellowOpaqueIsometric0.003
10Columbite-(Fe)6.0Black to brownish blackOpaqueOrthorhombic0.002