igneous

Scoria (Red Lava Rock)

Scoria (Vesicular Basalt/Andesite)

Hardness: 5-6 (Mohs scale); Color: Reddish-brown to dark red (due to oxidation); Luster: Dull/Earthy; Structure: Highly vesicular (pitted with air bubbles); Specific Gravity: Low (often floats in water temporarily until saturated).

Hardness: 5-6 (Mohs scale)
Color: Reddish-brown to dark red (due to oxidation)
Luster: Dull/Earthy

Identified March 29, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the rapid cooling of gas-rich, mafic or intermediate lava. The 'holes' are vesicles formed by trapped gas bubbles. Red coloring occurs when iron-rich minerals oxidize during or after eruption. Typically Holocene to Pleistocene in age.

Uses & applications

Used extensively in landscaping, drainage systems, gas grills (lava rocks), lightweight concrete aggregate, and high-temperature insulation.

Geological facts

Scoria differs from pumice because it has thicker cell walls and is denser; while pumice is felsic and light-colored, scoria is mafic and dark or red. Many 'lava rocks' in backyard grills are actually mined scoria.

Field identification & locations

Identify by its 'Swiss cheese' texture, rough/sharp surface, and very light weight. It is commonly found in volcanic fields like those in Iceland, Italy, the Canary Islands, and the Western United States (Arizona, New Mexico).

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral