Assertion: tourmaline | /r/AtLocation | pegmaitte
Facets:
value: widely
type: DEGREE
Source sentences:
text: Tourmaline occurs in pegmaittes,often associated with other gem minerals.
text: Tourmaline occurs in crystalline schists; in granites and granite pegmatites (especially elbaite); in gneiss, marbles and other contact metamorphic rocks (especially dravite, uvite).
text: Tourmalines occur widely within leucogranites and pegmatites that intrude the leucogranites in the south Tibetan plateau.