sedimentary

Conglomerate

Conglomerate (Rock composed predominantly of rounded clasts > 2mm)

AI-generated identification · may be incorrect

Hardness: Variable (typically 6-7 depending on cement and clasts); Color: Variable greys, tans, and browns; Luster: Dull/Earthy; Crystal Structure: Clastic (rounded fragments embedded in a finer matrix); Specific Gravity: 2.1-2.6

Hardness: Variable (typically 6-7 depending on cement and clasts)
Color: Variable greys, tans, and browns
Luster: Dull/Earthy

Identified March 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in high-energy environments such as riverbeds, alluvial fans, or beaches where water is strong enough to transport and round large stones. Over millions of years, these sediments are buried and lithified by mineral cements like calcite or silica.

Uses & applications

Used primarily in the construction industry as coarse aggregate for concrete and road base. Occasionally used as a decorative building stone or for ornamental landscaping.

Geological facts

Conglomerate is often called 'puddingstone' because the rounded stones look like raisins or nuts in a pudding. It is one of the most common rocks found on Mars by rovers, proving the past existence of ancient flowing rivers on the red planet.

Field identification & locations

Identify by looking for rounded pebbles or cobbles (not sharp angles) 'glued' together in a matrix. Commonly found along ancient or modern river channels and shorelines. Look for it in areas with exposed sedimentary layers.