Glauconitic Sandstone with Quartz and Calcite
Sandstone (Sedimentary Rock) with trace Glauconite and Quartz · Mineral Specimen / Common Rock
Crystal System
Trigonal (Quartz crystals) and Monoclinic (Glauconite Mica); Habit is massive, granular, and microcrystalline.
Mineral Group
Silicates (primarily Tectosilicates and Phyllosilicates)
Chemical Formula
SiO2 (Quartz), K(Fe,Al)2(Si,Al)4O10(OH)2 (Glauconite), CaCO3 (Calcite veins)
Formation Process
Sedimentary; formed by the accumulation of sand-sized grains cemented by minerals, with glauconite forming in shallow marine environments.
About This Crystal
A coarse, earthy specimen with a dull to sub-vitreous luster. It exhibits a speckled grey-green matrix with small translucent quartz grains and orange-tinted calcite or iron oxide staining.
Physical Characteristics
Color: Olive green to grey; Streak: White or light green; Cleavage: None visible in matrix; Fracture: Granular or uneven; SG: 2.4-2.8; Resilience: Brittle.
Optical Properties
Generally opaque in bulk. Individual quartz grains are transparent with refractive index ~1.54. No significant pleochroism or dispersion in this form.
Hardness & Durability
Origin Region
Global; commonly found in marine sedimentary basins such as the US Atlantic Coastal Plain or European Jurassic deposits.
Hardness & Durability
Variable; 5.5 to 7 on Mohs scale depending on cementation strength. Quartz grains are 7, but the sandstone matrix may crumble easily.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid acidic cleaners as they may dissolve calcite cement or veins. Store in a dry environment.
Rarity & Value
Common; low monetary value. Primarily of geological interest for environmental reconstruction or as building material.
Special Characteristics
Porous structure with characteristic 'greensand' coloration due to iron-rich glauconite; may show weak fluorescence if calcite is present.
Lore & History
Historically used as a soil conditioner (greensand) due to potassium content. Metaphysically associated with grounding and connecting to ancient Earth energies.