igneous

Basalt with Secondary Mineralization (Likely Zeolites or Calcite)

Aphanitic mafic volcanic rock with secondary mineral inclusions (e.g., CaAl2Si3O10·3H2O for Scolecite)

Hardness: 5-6 (base rock). Color: Dark grey to reddish-brown (weathered) with white/silvery fibrous inclusions. Luster: Dull/earthy for the matrix, silky to vitreous for the inclusions. Crystal Structure: Fine-grained/aphanitic matrix.

Hardness: 5-6 (base rock)

Identified February 21, 2026More igneous →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava at or very near the Earth's surface. The white fibrous mineral inclusions formed later through hydrothermal activity where mineral-rich water filled the gas vesicles (amygdules) within the basalt.

Uses & applications

Basalt is primarily used in construction (crushed stone, asphalt). The specific specimen has value for mineral collectors but lacks industrial utility due to its weathered state.

Geological facts

Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. The white fibrous minerals often found in these cavities are frequently zeolites, which are used industrially as molecular sieves for water purification.

Field identification & locations

Identify in the field by its heavy weight (high density), dark color, and vesicular (holey) or amygdaloidal (filled-hole) texture. Commonly found in volcanic fields like the Deccan Traps (India) or the Pacific Northwest (USA). For collectors, look for intact crystal terminations in the cavities.

Other igneous specimens

See all

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

mineral

Blue Apatite

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

mineral

Magnetite

Magnetite (Fe3O4)

mineral