Assertion: zircon | /r/HasProperty | rare
Facets:
value: within mafic rocks
type: LOCATION
value: within rare
type: DEGREE
Source sentences:
text: Zircon is rare within mafic rocks and very rare within ultramafic rocks aside from a group of ultrapotassic intrusive rocks such as kimberlites, carbonatites, and lamprophyre, where zircon can occasionally be found as a trace mineral owing to the unusual magma genesis of these rocks.
text: I understood your point that hadean zircon is rare but it needs to be phrased better.
text: The most prized zircon is the red gemstone, which is rare.