Amethyst is a variety of Quartz and the birthstone for February, its hardness is 7. It is available in pale to deep purple in wonderful fancy shapes, interesting cuts and large sizes as well as calibrated sizes. more...
Quartz sand 1. It is a hard, wear-resistant, stable chemical properties of silicate minerals. 2. Quartz sand color for the translucent milky white or colorless-shaped. 3. Indissolvable in acid, with high fire resistance properties. 4. It's used in follows industry. more...
