How to classify quartz sand?

Because of the high fire resistance of quartz, in industry it is often divided into ordinary quartz sand, refined quartz sand, high-purity quartz sand, fused silica sand and silicon powder, etc. So how to specifically classify quartz sand?

1.Ordinary quartz sand
SiO2 ≥ 90-99% Fe2O3 ≤ 0.06-0.02%, refractoriness 1750 ℃, the appearance of some large particles, the surface of yellow cysts. Particle size range of 5-220 mesh, according to user requirements particle size production. Main purposes: metallurgy, ink silicon carbide, glass and glass products, enamel, cast steel, water filtration, soda, chemical, spray noise and other industries.
2.Refined quartz sand
also known as pickling quartz sand, SiO2 ≥ 99-99.5% Fe2O3 ≤ 0.02-0.015%, selected high-quality ore from the complex processing. Particle size range of 5-480 mesh, according to user requirements, the appearance of white or crystalline. Main purposes: advanced glass, glass, refractories, smelting stone, precision casting, grinding wheel and so on. (Mm for the mm)
3.High purity quartz sand
SiO2 ≥ 99.5-99.9% Fe2O3 ≤ 0.005%, is the use of 1-3 grade natural crystal stone and high quality natural stone class, carefully selected, fine processing. Size range 1-0.5mm, 0.5-0.1mm, 0.1-0.01mm, 0.01-0.005mm, according to user requirements. (Mm for the mm)
4.Fused silica sand: Chemical composition:
SiO2 99.9-99.95% Fe2O3 5PPM-25PPM max Li2O 1-2PPM max Al2O3 20-30PPM max
K2O 20-25 PPM max Na2O 10-20 PPM max (PPM is parts per million)
Physical properties:
Appearance is colorless and transparent block, particles or white powder.
Relative specific gravity: 2.21;
Mohs hardness: 7.0;
PH: 6.0;