sedimentary

Flint with Fossil Inclusion

Cryptocrystalline quartz (SiO2) enclosing fossilized organic remains

Hardness of 7 on the Mohs scale, grayish exterior with dark patches, waxy to vitreous luster, conchoidal fracture, microcrystalline quartz structure.

Identified August 7, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, grayish exterior with dark patches, waxy to vitreous luster, conchoidal fracture, microcrystalline quartz structure.

Formed through the chemical replacement of limestone or chalk by silica-rich solutions in shallow marine environments during the Cretaceous period.

Historically used for making stone tools and fire-starting; today primarily collected as a geological specimen or used for lapidary work.

Flint nodules often form around organic nuclei such as sponges or shells, which can become fossilized within the stone.

Found commonly in chalk deposits and coastal gravel beds. Can be identified in the field by its characteristic conchoidal fracture and high hardness.

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone

Arenite

Quartz pebble

Silicon dioxide (SiO2)

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)