sedimentary
Sandstone with Secondary Mineral Encrustation
Arenite with Silica/Calcite deposits (SiO2 or CaCO3)
Hardness: 6-7 (if quartz-based); Color: Tan, brown, and grayish-white; Luster: Earthy to vitreous; Crystal Structure: Clastic grains with microcrystalline surface deposits; Cleavage: None; Specific Gravity: 2.2–2.8
- Hardness
- 6-7 (if quartz-based)
- Color
- Tan, brown, and grayish-white
- Luster
- Earthy to vitreous
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (if quartz-based); Color: Tan, brown, and grayish-white; Luster: Earthy to vitreous; Crystal Structure: Clastic grains with microcrystalline surface deposits; Cleavage: None; Specific Gravity: 2.2–2.8
Formation & geological history
Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The top layer shows secondary precipitation, where mineral-rich water flowed over the rock surface, leaving behind druzy or crust-like deposits, likely in a terrestrial or shallow marine environment.
Uses & applications
Common industrial uses include construction aggregate, glass making (if high silica), and decorative landscaping. This specific specimen serves as a geological study or hobbyist collection piece.
Geological facts
Sandstone makes up about 10–25% of the sedimentary rocks in the Earth's crust. This specimen exhibits 'druse' or mineral frosting, which occurs when crystals grow into an open void or on a rock's surface following its initial formation.
Field identification & locations
Identify in the field by its gritty texture (feels like sandpaper) and distinct layering. The white crust can be tested for calcite using a drop of vinegar (it will fizz if it is calcium carbonate). Commonly found in desert environments, riverbeds, and coastal cliffs.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary