sedimentary

Flint with Iron Oxide Inclusions

SiO2 (Microcrystalline Quartz) with Goethite/Limonite inclusions

Hardness of 7 on the Mohs scale. Colors include off-white, cream, or grey background with distinct brownish-red to yellowish-brown spots or patches. Luster ranges from waxy to vitreous. It has a conchoidal fracture with no true cleavage.

Identified August 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the diagenesis of siliceous oozes or chalk, where silica precipitates and replaces calcium carbonate, often millions of years ago during the Cretaceous period. The brownish spots are secondary iron oxide or hydroxide inclusions.

Uses & applications

Commonly collected as a beach pebble or geological specimen. Historically used for making stone tools, arrowheads, and early fire-starting flintlock weapons.

Geological facts

Flint is extremely durable and weather-resistant, which is why it often survives long journeys in riverbeds or coastlines as rounded pebbles, while softer surrounding chalk erodes away.

Field identification & locations

Easily identified on beaches by its smooth, water-worn exterior, distinct conchoidal chipping edges, and contrasting mineral inclusions. Frequently found along chalk cliffs and coastal beaches, such as the white cliffs of Dover.

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Sandstone or Siltstone

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Fossiliferous Concretion

Septarian Concretion containing Brachiopods/Crinoids

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Quartz pebble

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Generic Pebble / Rock Fragment

Lithic fragment / Weathered rock

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Banded Siltstone / Mudstone Pebble

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