The main mineral of quartzite is quartz, which may contain mica minerals, hematite and goethite. Its main chemical component is quartz-SiO 2 . Quartzite is generally a massive structure with a granular crystal structure and a crystalline aggregate. Quartz is also very rich in color. Common colors are green, gray, yellow, brown, orange, white, blue, purple, red, etc. Brass Angle Valves,1/2 Brass Angle Valve,3/4 Brass Angle Valve,2 Brass Angle Valve AS-SUR INDUSTRIAL VALVE CO., LTD. , https://www.assur-valve.com