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
Both graduated cylinders and beakers are pieces of laboratory glassware that have a specific function. Graduated cylinders typically are more accurate at reading the volumes of the liquid inside. Beakers are better for stirring and mixing liquids. Beaker A beaker is a simple laboratory piece of glassware that resembles a coffee mug without the handle. On its
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
Glass hardness is measured by four standard methods: the Mohs scratch test (qualitative, 5.5 for soda-lime, 6 for borosilicate, 7 for quartz), the Knoop hardness test (HK, used for brittle materials per ASTM C730), the Vickers hardness test (HV, with a diamond pyramid indenter per ASTM C1326), and the Brinell test (rarely used on glass).
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
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