XAGA :

Name given by Indians of California, to an obsidian

XALOSTOCITE :

Synonym for landerite, a pink or whitish grossular garnet

Etym. : from Xalostoc, city in Mexico

XANTHITHANE :

Synonym for Anastase

XANTHITE :

Name given to a variety of idocrase from Amity ( New-York ) of yellow to yellowish brown colour

XANTHOLITE :

Variety of impure cyanite

XENOTIME :

Phosphate of yttrium YPO₄ ; resembling strongly a zircon of which  it has the crystalline form and the appearance

XIUITL :

Aztec name for turquoise found near the city of Mexico

XYLONITE :

Commercial name for a celluloid

XYLOPAL :

Synonym for opalised wood