2. non-metallic minerals Is not the heated looks translucent? Brittle easily broken: full on sulfur, potassium, salt, fotfet Wright, sandstone, white clay, calcium.
2. แร่อโลหะ) is a mineral that is a heat conductor a translucent brittle break easily, including ฟลูออไร, phosphate rock, sand, salt and sulfur. Potassium calcium kaolin.