sedimentary
Jasper Conglomerate
Jasperoid Conglomerate (predominantly SiO2 with iron oxide impurities)
Hardness: 6.5-7 (Mohs); Color: Reddish-brown, gray, burgundy with darker clasts; Luster: Dull to waxy; Texture: Clastic with rounded grains; Specific Gravity: 2.6-2.9
- Hardness
- 6
- Color
- Reddish-brown, gray, burgundy with darker clasts
- Luster
- Dull to waxy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs); Color: Reddish-brown, gray, burgundy with darker clasts; Luster: Dull to waxy; Texture: Clastic with rounded grains; Specific Gravity: 2.6-2.9
Formation & geological history
Formed through the lithification of rounded pebbles and sand in high-energy aquatic environments, such as riverbeds or coastal wave zones, followed by silica-rich cementation. Many such specimens date to the Proterozoic or Paleozoic eras.
Uses & applications
Used primarily as decorative garden stones, in lapidary work for cabochons, and as a collectible specimen for geological study.
Geological facts
Conglomerates like this are often referred to as 'puddingstones' if the contrast between the matrix and pebbles is high. The red color is typically due to hematite (iron oxide) staining within the jasper pebbles.
Field identification & locations
Identify in the field by looking for rounded pebbles (clasts) fused together by a finer-grained matrix. Found commonly in glacial till, old riverbeds, and near the Great Lakes region in North America.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary