Assertion: cristobalite | /r/HasProperty | formed at 1470–1705 °c
Facets:
value: usually
type: TEMPORAL
value: in pure silica
type: LOCATION
value: previously
type: TEMPORAL
Source sentences:
text: As stated previously, cristobalite is usually formed at 1470–1705 °C, in pure silica, and its occurrence at 950 °C is rare, especially without the addition of alkali metals.