sedimentary
Sandstone Concretion with Quartz Center
Sedimentary Clastic Rock (SiO2 matrix with Quartz core)
Hardness: 6-7 (Mohs scale); Color: Earthy brown to gray exterior with white/translucent crystalline center; Luster: Dull/earthy (exterior), Vitreous (internal crystals); Structure: Clastic grain texture with a secondary mineral inclusion; Specific Gravity: 2.6-2.7.
- Hardness
- 6-7 (Mohs scale)
- Luster
- Dull/earthy (exterior), Vitreous (internal crystals)
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale); Color: Earthy brown to gray exterior with white/translucent crystalline center; Luster: Dull/earthy (exterior), Vitreous (internal crystals); Structure: Clastic grain texture with a secondary mineral inclusion; Specific Gravity: 2.6-2.7.
Formation & geological history
Formed through the accumulation of sand-sized mineral particles or rock fragments. The distinct center likely formed through 'concretion' or 'vug-filling,' where mineral-rich water deposited quartz or calcite in a void within the sandstone layers during diagenesis.
Uses & applications
Common sandstone is used in construction and paving. Specimens with aesthetic inclusions are kept by amateur collectors for study and display.
Geological facts
Sandstone preserves a record of ancient environments like deserts or riverbeds. The white 'patch' in this specimen indicates a localized mineral concentration where the rock was more porous or had a hollow cavity during its formation history.
Field identification & locations
Identify in the field by its gritty texture (feels like sandpaper) and visible layering or inclusions. Often found in riverbeds, cliffs, and sedimentary basins. Collectors look for unique color patterns or 'eyes' like the one seen here.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary