Bastnasite-(Ce): Gemstone Information
Bastnasite-(Ce) has been found as dark orange brown to brown facetable crystals in Pakistan. The composition is (Ce,La)(CO3)F and crystals belong to the hexagonal system. The hardness is 4–4.5 and the SG 4.78–5.20. The RI for the ordinary and extraordinary rays is 1.72 and 1.82 respectively,uniaxial positive. Specimens show a characteristic RE absorption spectrum with bands at 690, 660, 610, 585 560 530 and 525–500 nm.