Cristobalite

Description

A translucent Quartz mineral named after Cerro San Cristobal, Mexico where it was first identified in 1887. Cristobalite is a natural, refractory material formed in volcanic rock. It can be made synthetically when quartz is heated above 1050 C. Small amounts of cristobalite in a ceramic glaze formula minimize crazing. Opals contain masses of microscopic cristobalite crystals.

Synonyms and Related Terms

cristobalita (Esp.); cristobalite (Fr., Port.)

Physical and Chemical Properties

• Luster=Glassy
• Streak = white
• Nonfluorescent

Composition	SiO2
CAS	14464-46-1
Mohs Hardness	6.5
Density	2.2 g/ml
Refractive Index	1.485-1.487

Comparisons

Properties of Common Gemstones

Resources and Citations

• WebMinerals: Cristobalite

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 647

• Robert Fournier, Illustrated Dictionary of Practical Pottery, Chilton Book Company, Radnor, PA, 1992

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997