Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (individual grains); Color: Yellow, tan, orange-brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8

Formation & Geological History

Formed through the accumulation of sand-sized mineral grains (mostly quartz) in environments like deserts, riverbeds, or beaches. The yellow-orange color indicates the presence of iron oxide minerals that act as a cementing agent between the grains.

Uses & Applications

Commonly used as a building material, in glass manufacturing (if high purity quartz), and as an abrasive. For collectors, it serves as a common specimen for studying sedimentary layers.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The famous 'Wave' formation in Arizona is a classic example of cross-bedded sandstone that shows ancient wind patterns.

Field Identification & Locations

Identify in the field by its gritty, sandpaper-like texture and visible layers (bedding). It can be found globally in outcrop formations and riverbeds. Collectors should look for unique banding or fossil inclusions.

Identified on: 5/8/2026

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