Flint
Rock made of quartz
Common
The kind of chert found in chalk: nodules dark and glassy inside under a white rind, breaking into edges sharp enough to cut. The stone of the Stone Age, knapped into blades for three million years and struck on steel to start fires.
Rock
- Kind of rock
- Chemical sedimentary rock
- Rock family
- Limestone and chalk
- Texture
- cryptocrystalline (crystals too small to see under a lens)
- How it forms
- Silica, probably from sponge spicules, gathers into nodules and bands in chalk as water is squeezed out during burial.
- Uses
- Knapped blades and scrapers, struck on steel for fire and in the flintlock, and walls of knapped flint from Roman forts to English churches.
Identity
- Also known as
- Flintstone
Crystallography
- Habits
- Nodular, Massive
Physical properties
- Luster
- Waxy, Vitreous
- Colors
- dark gray, black, brown, white, green
- Transparency
- Opaque
Geology
- Origins
- Sedimentary
- Host rocks
- Limestone and chalk
- Geography
- England, France (Paris Basin), Belgium (Spiennes, Obourg), Denmark (Hov, Thy), USA (Flint Ridge, Ohio)
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- Flint. Wikipedia.
- Chert. Wikipedia.
- Chalk. Wikipedia.
- C. R. Hallsworth, R. W. O’B. Knox, BGS Rock Classification Scheme, Volume 3: Classification of sediments and sedimentary rocks (Research Report RR 99-03). British Geological Survey, 1999.
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