sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: 6-7 (quartz clasts), Color: Buff/tan matrix with gray/translucent clasts, Luster: Dull/earthy matrix with vitreous clasts, Structure: Clastic, coarse-grained, poorly sorted.
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Physical properties
Hardness: 6-7 (quartz clasts), Color: Buff/tan matrix with gray/translucent clasts, Luster: Dull/earthy matrix with vitreous clasts, Structure: Clastic, coarse-grained, poorly sorted.
Formation & geological history
Formed by the lithification of rounded gravel and pebbles, typically in high-energy environments such as riverbeds, alluvial fans, or beaches. Matrix is often sand or silt cemented by silica or calcite.
Uses & applications
Primarily used as a heavy construction material, road base, and occasionally as decorative stone or for building facings if aesthetically pleasing.
Geological facts
Conglomerates are often referred to as 'puddingstone' because they look like raisins or fruit in a cake. They are excellent indicators of ancient high-energy water flow environments.
Field identification & locations
Identify in the field by looking for rounded, smooth pebbles larger than 2mm embedded in a finer-grained matrix. Found globally in ancient river systems and sedimentary basins.
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