sedimentary
Conglomerate
Conglomerate (Clastic sedimentary rock)
Hardness: 6.5-7 (variable); Color: Grey, brown, or tan matrix with white quartz inclusions; Luster: Dull to vitreous; Structure: Clastic with rounded clasts; Cleavage: None
- Hardness
- 6
- Color
- Grey, brown, or tan matrix with white quartz inclusions
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7 (variable); Color: Grey, brown, or tan matrix with white quartz inclusions; Luster: Dull to vitreous; Structure: Clastic with rounded clasts; Cleavage: None
Formation & geological history
Formed through the lithification of rounded gravel and boulders, typically in high-energy environments like riverbeds, alluvial fans, or beaches. These sediments are cemented together over millions of years by minerals like silica or calcite.
Uses & applications
Used primarily in the construction industry as coarse aggregate for concrete and road building. Occasionally used as a decorative stone in architecture or landscaping.
Geological facts
Conglomerates are often referred to as 'puddingstone' because they resemble a fruit pudding. They are significant indicators of past water flow and energy levels in ancient geological environments.
Field identification & locations
Identify in the field by looking for rounded pebbles or cobbles 'glued' into a finer matrix. Often found in ancient river systems or glacial deposits. Common globally.
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