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Cryptocrystalline identification and geology

Describing a material composed of crystals so small that they cannot be resolved under a standard optical microscope, typically less than 1 micrometer. Cryptocrystalline materials appear amorphous under ordinary examination but reveal crystalline order through X-ray diffraction or electron microscopy. The term is most commonly applied to varieties of quartz such as chalcedony, agate, jasper, and chert. Field: mineralogy. Example: Agate is a cryptocrystalline variety of quartz in which alternating bands of chalcedony and microcrystalline quartz produce the characteristic banding pattern visible in polished specimens.. Related terms: Amorphous, Microcrystalline, Chalcedony, Chert.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

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GeoMiner
Last updated
2026-03-30T15:19:41.970235+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Cryptocrystalline mean in geology?
Describing a material composed of crystals so small that they cannot be resolved under a standard optical microscope, typically less than 1 micrometer. Cryptocrystalline materials appear amorphous under ordinary examination but reveal crystalline order through X-ray diffraction or electron microscopy. The term is most commonly applied to varieties of quartz such as chalcedony, agate, jasper, and chert.
What is an example of Cryptocrystalline?
Agate is a cryptocrystalline variety of quartz in which alternating bands of chalcedony and microcrystalline quartz produce the characteristic banding pattern visible in polished specimens.
Which earth-science field uses the term Cryptocrystalline?
Cryptocrystalline is used in mineralogy.
Which terms are related to Cryptocrystalline?
Related terms in this reference are Amorphous, Microcrystalline, Chalcedony, Chert.

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