sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: 6-7 (based on quartz content); Color: White, tan, brown, reddish; Luster: Vitreous to earthy; Crystal Structure: Amorphous clasts within a matrix; Cleavage: None; Specific Gravity: 2.6-2.9
- Hardness
- 6-7 (based on quartz content)
- Color
- White, tan, brown, reddish
- Luster
- Vitreous to earthy
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Physical properties
Hardness: 6-7 (based on quartz content); Color: White, tan, brown, reddish; Luster: Vitreous to earthy; Crystal Structure: Amorphous clasts within a matrix; Cleavage: None; Specific Gravity: 2.6-2.9
Formation & geological history
Formed by the consolidation and lithification of rounded gravel and pebbles, usually in high-energy environments like riverbeds or alluvial fans. Can be any geological age from Precambrian to Cenozoic.
Uses & applications
Used primarily in the construction industry as coarse aggregate for concrete and roadbeds. Also used as decorative stone in landscaping or for architectural facades.
Geological facts
Conglomerate is often nicknamed puddingstone because it looks like raisins or nuts in a cake. It can serve as a reservoir rock for petroleum and natural gas due to its porosity.
Field identification & locations
Identify by looking for rounded clasts (pebbles) larger than 2mm embedded in a finer-grained matrix. Look for them in areas with ancient river deposits or coastal outcrops.
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