Lava Rock (Basalt with Limonite)
Vesicular Basalt with Goethite/Limonite staining · Mineral Specimen / Decorative Stone / Igneous Rock
Crystal System
Amorphous to Microcrystalline (Glassy/Aphanitic matrix); Orthorhombic (Goethite)
Mineral Group
Silicates (Mafic Silicate Rock) and Oxides (Iron Oxides)
Chemical Formula
(Mg, Fe, Al, Ca) silicate (Matrix) with FeO(OH)·nH2O (Oxide staining)
Formation Process
Igneous (Extrusive). Formed from the rapid cooling of magnesium-rich and iron-rich lava. The holes (vesicles) are created by trapped gas bubbles during solidification.
About This Crystal
An opaque, dark grey to black volcanic rock with a vesicular (pitted) texture. It features prominent reddish-orange to ochre oxidization patches. The luster is dull to sub-metallic on fresh surfaces and earthy on oxidized sections.
Physical Characteristics
Color: Charcoal black with rust-orange staining; Streak: Black or brownish; Cleavage: None; Fracture: Uneven to conchoidal (glassy portions); SG: 2.8–3.0; Fluorescence: None.
Optical Properties
Opaque; No birefringence or pleochroism visible in hand specimen. It lacks transparency or significant light play due to its dense, fine-grained volcanic nature.
Hardness & Durability
Origin Region
Worldwide; notably Hawaii, Iceland, Italy (Etna/Vesuvius), and the Pacific Northwest (USA). Found in volcanic fields and oceanic crust.
Hardness & Durability
Mohs Hardness: 5 to 6. Moderately durable but brittle due to vesicles. High heat resistance; susceptible to mechanical weathering if heavily oxidized.
Care & Maintenance
Clean with warm soapy water and a soft brush to remove dust from pits. Avoid harsh chemicals that may react with iron oxides. Store in a dry environment to prevent further uncontrolled oxidation.
Rarity & Value
Common. Abundant globally. Value is low for raw specimens, though specific scoria or basalt types are valued for landscaping, filtration, or aquarium decor.
Special Characteristics
Vesicular texture (preserved gas bubbles); presence of secondary iron oxide staining (limonite) providing the 'rusty' orange color contrast.
Lore & History
Historically used for millstones and construction material by Romans. Metaphysically associated with the Root Chakra, grounding, strength, and the element of fire and earth combined.