Lava Rock
What is Lava Rock?
Lava rock is an extrusive igneous rock formed from the rapid cooling of lava. It is typically dark-colored, often black or gray, and can have a vesicular texture due to trapped gas bubbles. The composition varies depending on the source of the lava, but it is generally rich in silica and other minerals. Lava rock is commonly found near volcanoes and is used in landscaping, construction, and as a decorative element.
Optical Properties
- Refractive Index
- Variable, depends on mineral composition
- Birefringence
- Variable, depends on mineral composition
- Pleochroism
- None
- Optical Character
- Variable, depends on mineral composition
- Dispersion
- Not applicable
Discover Values
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Lava Rock before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Lava Rock Localities Map
See where Lava Rock is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Black, gray, brown, reddish-brown
- Hardness (Mohs)
- 5 to 6
- Density
- 2.2 to 3.0 g/cm³
- Luster
- Vitreous to dull
- Crystal System
- Amorphous or microcrystalline
Chemical Properties
- Chemical Formula
- Variable, depends on the specific lava composition. Often includes silicates like (Na,Ca)(Si,Al)2(Si2O6)
- Elements
- Si, O, Al, Fe, Mg, Ca, Na, K
Also Known As
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Lava Rock FAQs
How do I identify Lava Rock?
Lava Rock can be identified by its hardness of 5 to 6 on the Mohs scale, Black color, Vitreous to dull luster, Amorphous or microcrystalline crystal system. Look for these key characteristics when examining specimens.
What color is Lava Rock?
Lava Rock typically appears in Black, gray, brown, reddish-brown. Color can vary depending on impurities and formation conditions.
How hard is Lava Rock?
Lava Rock has a hardness of 5 to 6 on the Mohs scale. This gives it moderate hardness.