Lava Rock (Scoria) | Gemopedia
Also known as scoria, lava rock is formed from solidified volcanic lava. A defining feature of this rock is cavities caused by trapped gas bubbles. Unlike pumice, however, lava rock does not float on water. The unique look of this highly porous rock, along with its relatively light weight, makes it popular for jewelry and ornamental carvings.
Alternate
Names
Names
Scoria
Colors
Black, Dark Gray, Deep Reddish Brown
Lava Rock (Scoria) Classification
Common Name
Lava Rock (Scoria)
Species
NA
Variety
Colors
Black, Dark Gray, Deep Reddish Brown
Alternate Names
Scoria
Gemstone Groups
Key Separations
Appearance and SG
Comments
Scoria is an igneous rock that is formed from solidified lava. The cavities are caused by trapped gas bubbles. Scoria can be separated from pumice because it will sink in water because it has an SG greater than 1.
Lava Rock (Scoria) Optical Properties
Transparency
Opaque
Refractive Index
Birefringence
Optic Character
NA
Optic Sign
Polariscope Reaction
Fluorescence
SWUV:
LWUV:
CCF Reaction
Pleochroism
None
Dispersion
Strength: none
Comments
Lava Rock (Scoria) Chemistry & Crystallography
Chemical Name
Chemical Formula
Synthesis
Crystal System
NA
Classification
Rock
Nature
Natural
Crystallinity
Aggregate
Comments
Lava Rock (Scoria) Characteristic Physical Properties
Hardness
Streak
Specific Gravity
Toughness
Inclusions
Lava rock or scoria will have rounded or elongated cavities.
Luster
Vitreous
Stability
Fracture
Cleavage
None
Comments
