Volcanic Gravel (Basalt and Scoria)
Image: <a href="//commons.wikimedia.org/wiki/User:Reykholt" title="User:Reykholt">Reykholt</a> (CC BY-SA 4.0)
Mineral NameVolcanic Gravel (Basalt and Scoria)
Chemical FormulaPrimarily silicates of iron, magnesium, and calcium
Mohs Hardness5
Crystal Systemamorphous
Lusterdull
Streak Colorgrey to reddish-brown
CleavageNone observed (rock)
Fractureuneven
Specific Gravity2.9
Colorsdark grey, black, reddish-brown, light grey
Transparencyopaque
Type LocalityKleifarvatn, Reykjanes, Iceland
Mineral GroupSilicates (Igneous Rock)
Usesconstruction aggregate, road material, landscaping
Associated Mineralsplagioclase, pyroxene, olivine
Raritycommon
Description
A close-up view of mixed volcanic gravel, featuring angular to sub-rounded fragments of dark grey basalt and reddish-brown scoria, intermingled with dark soil.
Geological Context
These rocks are typical of Iceland's active volcanic environment, formed by the rapid cooling of mafic lava flows. The varied colors reflect different compositions and degrees of oxidation.
