What Are Hyaloclastites and How Do They Form?
Hyaloclastites are an accumulation of angular basaltic glass fragments or their breccia. A breccia is a rock with volcanic fragments cemented in a fine-grained matrix.
Volcanic glass
What Is Palagonite Including Tuff
Palagonite is a yellow, yellow-orange, or brownish material formed from the alteration of basaltic or glass with a chemical composition like basalt. However, it may
What Is Tachylite Rock?
Tachylite rock is an opaque black or brown basaltic glass with a greasy look and a resinous luster. It is a natural volcanic glass that
What Is Sideromelane
Sideromelane is a transparent or clear brownish or yellow-brown colored basaltic glass. It forms from rapid quenching of basaltic magma mostly (but not exclusively) in
Here Are 11 Most Fascinating Obsidian Types or Varieties
Obsidian is a natural volcanic glass often called a volcanic or extrusive igneous rock. IUGS considers it a mineraloid since it has > 80% glass.
Obsidian: A Hard, Brittle Natural Volcanic Glass or Rock
Obsidian is a felsic, naturally occurring volcanic glass. It has 69-77% silica and is relatively high in alkalis (>7%) and low in iron and magnesium
Pumice: A Frothy, Light-Colored Volcanic Rock with Many Uses
Pumice is a very low-density, form-like, mostly light-colored glassy volcanic rock with a vesicular texture, not a mineral. This rough, porous rock forms from mostly
Understanding Scoria: A Highly Vesiculated Dark-Colored Volcanic Rock
Scoria is a mafic to intermediate highly vesiculated dark gray, black, reddish, or brown extrusive igneous rock (volcanic glass). This vesicular textured pyroclastic rock forms
What Are Apache Tears or Obsidian Balls?
Apache tears (marekanite or obsidianites) are smoky, dark gray, gray-brown, or black indented tear-shaped, rounded, or subangular small obsidian balls, pebbles, or nodules measuring up