Quartz

UNB-2017-0128Minerals » Tectosilicates

Description

Quartz Geode [SiO2] A cavity within dark, fine-grained host rock is lined by chalcedony/agate and colourless to milky quartz, grading inward to pale-to-medium violet amethyst [SiO₂]. The amethyst occurs as closely intergrown, euhedral crystals projecting into the open cavity, with well-developed rhombohedral terminations and vitreous lustre. Minor yellow-brown to orange staining occurs locally along the cavity margins.

Specifications

Object name	Quartz
ID	UNB-2017-0128
Legal status	Permanent collection
Category	Mineral
Classification	Mineral group: Tectosilicates
Composition	CaB2Si2O8(OH,F)2 (Ca,Na2,K2)Al2Si4O12•6H2O (Ca,Na)AlSi2O8 (Na2,K2)Al2Si4O12•2H2O (Na,Ca)4(Al,Na)3Si9O24(Cl,CO3)2 (MAlO2)(SiO 2)x(H2O)y (Na,K)AlSiO4 Na2Al2Si3O10·2H2O KAlSi3O8 Na2Ca2Al6Si9O30·8H2O K(AlSi2O6) CaAl2Si4O12·4H2O Pectolite NaCa2Si3O8(OH)2H2O with trace amounts of copper (Ca,Na)(Al,Si)4O8 SiO2 with water inclusion (Na,Ca)4-8Al6Si6(O,S)24(Cl,SO4)1-2 Na8(Al6Si6O24)Cl2 CaAl2Si3O10·3H2O SiO2 (Cs,Na)2Al2Si4O12·2H2O (Na, Ca)(Al, Si)AlSi2O8 KAlSi3O8 (Na,K)AlSi3O8 (Na,K)AlSi3O8 CaAl2Si2O8 SiO2
Origin	Brazil
Pieces	1
Partial	No
Measurements	20cm x 12cm x 11cm

Map of Origin

Publications

Chesterman, C.W. 1979. Audubon Society, Field Guide to North American Rocks and Minerals. Knopf.