Quartz-based dimension stone — natural stone that is sawed, cut, or split, not molded or aggregated from fragments — is classified for structural and building use under its own ASTM specification. This page covers that classification and a documented safety finding specific to a different, man-made form of quartz: engineered stone surfaces.
What is it?
Quartz-based dimension stone is classified under ASTM C616 into three types by free silica content — sandstone (Type I), quartzitic sandstone (Type II), and quartzite (Type III) — with physical requirements covering absorption by weight, density, compressive strength, modulus of rupture, and abrasion resistance. The specification explicitly excludes molded, cast, or otherwise artificially aggregated units, as well as crushed and broken stone.
Why should I use it?
- A dedicated specification classifies natural quartz-based stone into three types with clear physical requirements — see “What is it?” above.
- A separate, man-made form of quartz — engineered stone surfaces — has a directly measured safety consideration worth knowing — see Limitations.
How it’s used
In Plastics & Polymers, Quartz is used as a filler; separately, quartz-based dimension stone (sandstone, quartzitic sandstone, or quartzite) is classified for structural and building use under ASTM C616.
Limitations — when it isn’t the right choice
- Engineered quartz surfaces — a man-made composite of crushed quartz and resin, not the natural dimension stone covered by ASTM C616 — carry a real, well-documented cutting hazard. A 2022 peer-reviewed study characterizing dust from machined engineered stone found respirable crystalline silica content of 70–91% in the tested products, compared to far lower levels in natural stone (30% in black granite, 11% in white marble, 3.5% in white granite). The dust produced was extremely fine — 90% of particles measured 190–825 nanometers — with a specific surface area of 1.43–2.73 m²/g, versus 0.44–0.88 m²/g for natural stone dust. This was documented for the specific engineered stone samples tested during machining, a fabrication-stage risk distinct from packaged raw quartz or from the natural stone covered by C616; it should not be assumed identical for every commercial engineered quartz product without checking its own fabrication safety data.
