Sandstone Nodule
Sedimentary Rock var. Quartz Sandstone · Mineral Specimen
Crystal System
Trigonal (Quartz grains), Amorphous/Aggregate rock structure
Mineral Group
Silicates (framework silicates/tectosilicates)
Chemical Formula
SiO2 (with various mineral cements like CaCO3, Fe2O3, or clay minerals)
Formation Process
Sedimentary accumulation of sand-sized mineral grains compacted and cemented over geological time
About This Crystal
An opaque, weathered, brownish-red rounded nodule with a rough, granular surface texture characteristic of weathered quartz sandstone
Physical Characteristics
Color is reddish-brown; white streak; no true cleavage; uneven to granular fracture; specific gravity around 2.2 to 2.6; brittle tenacity
Optical Properties
Aggregated individual quartz grains show typical uniaxial positive optical character under microscopic examination, but the rock itself is opaque and non-pleochroic
Hardness & Durability
Origin Region
Found globally in sedimentary basins, riverbeds, and desert regions
Hardness & Durability
Mohs hardness varies from 6 to 7 depending on the cement matrix; moderate toughness; resistant to weathering but friable if poorly cemented
Care & Maintenance
Wash with warm soapy water and a soft brush; avoid harsh acids if carbonate cement is present; store separately to prevent scratching softer stones
Rarity & Value
Common; primarily of educational and geological interest with very low monetary value
Special Characteristics
Shows granular texture with iron oxide staining giving the reddish coloration
Lore & History
Used traditionally to symbolize grounding, endurance, and connection to the Earth element, though without scientific backing