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.
Glassy or vitreous texture
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
What Are Pele’s Tears and How Do They Form?
Pele’s tears are small jet-black teardrop, obovoid, spherical, or cylindrical-shaped volcanic glass droplets formed when tiny blobs of ejected magma cool quickly. They often precede
How Do the Mystical Pele’s Hair Form?
Pele’s hair is a formal geological term that volcanologists give to the golden-brown, fiber or thread-like strands of volcanic glass formed naturally from blowing out
12 Examples of Volcanic Glass Types You Should Know
Volcanic glass is an amorphous or uncrystallized extrusive igneous rock. It forms from the rapid cooling or quenching of magma that doesn’t allow crystallization. Such
Formation and 7 Rocks with Vitreous or Glassy Rock Texture
Glassy or vitreous rock texture describes the texture of amorphous solid volcanic glasses. Rocks with this texture form when magma or lava cools rapidly or