Amethyst vs Beta quartz
Amethyst and Beta quartz share a composition and differ on 2 measured properties — the question a reader asks about any pair of polymorphs.
Amethyst vs Beta quartz
These are different kinds of thing (mineral variety, mineral). Fewer properties mean the same thing across both, so a like-for-like reading may not be available.
Beta quartz
SiO2
The high-temperature form of quartz — hexagonal rather than trigonal above 573 °C, and the reason a fired ceramic body can crack on cooling.
| Property | Amethyst | Beta quartz |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | trigonal | hexagonal |
| Density | 2.65–2.66 g/cm³ higher | 2.53 g/cm³ |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 1670 °C |
| Mohs hardness Only one of the two has a figure we can stand behind, so there is nothing to compare. | 7 | Not known |