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Cordierite

Silicate Minerals

Cordierite, called iolite in gemology, is a magnesium iron aluminium cyclosilicate in which iron is almost always present, and a solid solution exists between Mg-rich cordierite and Fe-rich sekaninaite. It was discovered in 1813 in specimens from Nijar, Almeria, Spain, and is named after the French geologist Louis Cordier. It typically occurs in contact or regional metamorphism of pelitic rocks and is especially common in hornfels, and it is synthesized for high-temperature uses such as catalytic converters and pizza stones. In this atlas it is the mineral species behind the gemstone iolite.

Facts
Kind
Mineral 1
Chemical Formula
(Mg,Fe)2Al4Si5O18 1
Hardness (Mohs)
7.25 1
Commonly cited range is 7 to 7.5 on the Mohs scale; 7.25, the midpoint, is used here.
Classification
Crystal System
Orthorhombic 1
Classification
Silicate Mineral 1
Use
Gemstone 1
Connections

Classified As

Entity-backed identity for the material classification this material already carries as an enum fact, pointing at the class subcategory of the same name. The enum fact itself stays on the entity unchanged.

Crystallizes In System

Entity-backed identity for the crystal system this mineral already carries as an enum fact, phase 3 bucket conversion (docs\design_entity_backed_browse_buckets_20260928.md, w-bucketconv-divmore2-0929). The original fact stays on the entry unchanged.

In Discipline

In the Other Atlases
Sources
1. Cordierite (Wikipedia)
Wikimedia Foundation
  • Cordierite, lead paragraph
    Cordierite (mineralogy) or iolite (gemology) is a magnesium iron aluminium cyclosilicate.
  • Cordierite, article text
    It is especially common in hornfels produced by contact metamorphism of pelitic rocks.
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