sedimentary
Siltstone or Limestone Beach Pebble
Siltstone / Micritic Limestone
Hardness: 3-5.5 (Mohs scale); Color: Gray to light gray; Luster: Dull/Earthy; Structure: Fine-grained clastic; Cleavage: None (conchoidal fracture); Specific Gravity: 2.3-2.7
- Hardness
- 3-5
- Color
- Gray to light gray
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-5.5 (Mohs scale); Color: Gray to light gray; Luster: Dull/Earthy; Structure: Fine-grained clastic; Cleavage: None (conchoidal fracture); Specific Gravity: 2.3-2.7
Formation & geological history
Formed through the lithification of silt or calcium carbonate mud in low-energy aquatic environments. This specimen has been rounded and smoothed by wave action on a beach or riverbed over hundreds to thousands of years.
Uses & applications
Primarily used as landscaping stone, river rock for decorative gardens, or as a natural collector's souvenir for its unique heart-like shape.
Geological facts
The 'heart' or triangular pattern within the stone is likely caused by differential weathering of a harder inner nodule or a distinct sedimentary layer. Such patterns are common in water-worn clastic rocks.
Field identification & locations
Identify by its smooth, matte texture and fine grain. Can be found on pebbly beaches and in riverbeds globally. It lacks the sparkle of crystalline rocks like quartzite.
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