sedimentary or igneous

Crushed Stone (Likely Limestone or Granite)

Calcium Carbonate (CaCO3) for Limestone / Quartz and Feldspar for Granite

Hardness: 3-5 (Limestone) to 6-7 (Granite); Color: Grey, blue-grey, or white; Luster: Dull to vitreous; Crystal structure: Microcrystalline to coarse-grained; Angular cleavage resulting from mechanical crushing.

Hardness: 3-5 (Limestone) to 6-7 (Granite)
Color: Grey, blue-grey, or white
Luster: Dull to vitreous

Identified June 14, 2026More sedimentary or igneous →

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Physical properties

Formation & geological history

Formed through mechanical crushing of bedrock. Limestone forms in shallow marine environments; Granite forms from cooling magma deep underground. These are typically derived from Paleozoic to Mesozoic era formations.

Uses & applications

Used primarily as construction aggregate for road base, railway ballast, concrete, asphalt, and landscaping drainage.

Geological facts

Crushed stone is one of the most accessible and important geological materials for infrastructure globally. Most modern roads are built on a foundation of these fragments.

Field identification & locations

Identify in the field by its angular, sharp edges (man-made crushing) and uniform size distribution. Often found on gravel driveways, railway tracks, and construction sites.

Other sedimentary or igneous specimens

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Pyrite

Iron Sulfide (FeS2)

mineral

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sedimentary rock

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

igneous

Garnet in Host Rock

Garnet Group (A3B2(SiO4)3)

metamorphic

Fluorite with Quartz coating

Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)

mineral

Opal

Hydrated Silica (SiO2·nH2O)

mineral