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Streak identification and geology

The color of a mineral in powdered form, obtained by rubbing the mineral across an unglazed porcelain plate streak plate . Streak is more diagnostic than the mineral's external color because it is less affected by trace impurities, inclusions, and surface weathering. Minerals harder than the streak plate 6.5–7 will not produce a streak and instead scratch the plate. Field: mineralogy. Example: Hematite can appear silver, red, or brown in hand specimen, but its streak is always reddish-brown—this consistency makes streak one of the most reliable properties for identifying hematite.. Related terms: Hardness, Luster, Color, Porcelain.

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.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.096023+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 Streak mean in geology?
The color of a mineral in powdered form, obtained by rubbing the mineral across an unglazed porcelain plate streak plate . Streak is more diagnostic than the mineral's external color because it is less affected by trace impurities, inclusions, and surface weathering. Minerals harder than the streak plate 6.5–7 will not produce a streak and instead scratch the plate.
What is an example of Streak?
Hematite can appear silver, red, or brown in hand specimen, but its streak is always reddish-brown—this consistency makes streak one of the most reliable properties for identifying hematite.
Which earth-science field uses the term Streak?
Streak is used in mineralogy.
Which terms are related to Streak?
Related terms in this reference are Hardness, Luster, Color, Porcelain.

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