Quartz and calcite are common minerals in the rocks around the world. Both minerals form in a variety of colors, such as purple, white, brown, gray and colorless, which at times makes them appear similar. However, these two minerals have many distinctively different physical and chemical properties that differentiate them. Hardness Mineral hardness is a

Fused silica and fused quartz are both non-crystalline forms of silicon dioxide (SiO₂) — chemically identical but distinguished by purity, manufacturing route, and OH content. Fused quartz is made by melting naturally occurring crystalline quartz at 2,000+ °C; fused silica is synthesized from gaseous SiCl₄ via flame hydrolysis or plasma deposition, producing higher purity (≥

Quartz is a crystalline form of silicon dioxide (SiO₂) — the second most abundant mineral in the Earth’s crust and one of the most useful natural materials in science. Pure quartz is colorless, transparent, has a hardness of 7 on the Mohs scale, and exhibits piezoelectric properties. In optics and spectroscopy, the term “quartz” most

Fused quartz is a non-crystalline (glass) form of silicon dioxide (SiO₂) made by melting high-purity natural quartz crystals at temperatures above 2,000 °C. It exhibits extremely low thermal expansion (0.55 × 10⁻⁶/°C), high optical transmission from 185 nm UV through 3,500 nm IR, a working temperature up to 1,100 °C, and chemical resistance against most

To tell glass from quartz, use 5 quick tests: (1) UV transmission — quartz transmits UV-C down to 185 nm, glass blocks below 320 nm; (2) thermal shock — quartz survives 1,100 °C → ice water; glass shatters above 200 °C ΔT; (3) Mohs scratch — quartz scratches glass (7 vs 6); (4) thermal expansion

One of the most important thermal properties of fused quartz is its extremely low coefficient of thermal expansion: 5.5 x 10-7 /°C (20-320 °C). Its coefficient is 1/34 that of copper and only 1/7 of borosilicate glass. This makes the material particularly useful for optical flats, mirrors, furnace windows and critical optical applications which require minimum