MT5: Minerals with Nonmetallic Luster
- Hardness <5.5
- Streak that is faint, white or appears white like
Cleavage |
Other |
Mineral |
None or Indistinct |
White, gray, apple green in color; pearly luster; greasy feel; may have a slight streak (see also table MT6) |
Talc Mg3Si4O10(OH)2 |
White in color; satiny or silky luster; fibrous fracture (see also table MT6) |
Gypsum CaSO4 2H2O |
|
White in color; dull luster; greasy feel; earthy odor; powdery |
Kaolinite Al2Si2O5(OH)4 |
|
Multicolored green, gray, black in color; dull to greasy luster; slight greasy feel; massive fibrous |
Serpentine Mg3Si2O5(OH)4 |
|
Poor cleavage |
Light green to medium green, brown, yellow in color; vitreous luster; six-sided crystals common; may show one poor cleavage |
Apatite Ca5(PO4)3(F,Cl,OH) |
Buff, gray, white, pinkish in color; small, rhombohedral crystals or massive; three cleavages not at 90 degrees but may be indistinct; reacts slowly with acid or not at all unless powdered (see also table MT6) |
Dolomite CaMg(CO3)2 |
