The Warner Mountains are famous for the variety of obsidian and for the four mines where the public can, with a permit, collect it. The four mines – Pink Lady, Lassen Creek Rainbow, Needles and Middle Fork Davis Creek – are all located within a few miles of US Hwy 395 in northeast California.

Andesite is a fine-grained, extrusive igneous rock composed mainly of plagioclase with other minerals such as hornblende, pyroxene, and biotite.

ABSTRACT. A variety of obsidian from Glass Buttes, Oregon, known as “fire” obsidian and named for thin layers showing various colors, was investigated with field-emission scanning electron microscopy, X-ray energy-dispersive spectroscopy, electron back-scatter diffraction, and optical spectroscopy methods.

pumice stone

Scoria is an extremely vesicular basaltic lava with very small (< 1mm) vesicles. Landscapers know this rock as lava rock. Pumice is a froth of felsic volcanic glass. It is rock foam with so much air in its structure that it often floats on water.

The bobbing observed in laboratory experiments of pumice floatation is explained by trapped gas expanding during the heat of day, which causes the stones to temporarily float until the temperature drops.

Pumice is a lightweight, bubble-rich rock that can float in water. It is produced when lava goes through rapid cooling and loss of gases. Large “rafts” of the volcanic rock are more likely to form when a volcano is located in more shallow waters, say experts.

Pumice stones are an inert, non toxic substance. They may experience some irritation in their mouth from the chewing.

A pumice stone can be used to remove the dead skin from a callus or corn. Reducing the size of the callus or corn may result in less pressure or friction and less pain. Soak your foot or other affected area in warm, soapy water for 5 minutes or until the skin softens. Wet the pumice stone.

You can purchase a pumice stone at local beauty supply stores or grocery stores. Some stores offer a double-sided pumice stone. These stones have an abrasive side for rougher skin and a softer side for more sensitive areas or buffing.

Pumice, a very porous, frothlike volcanic glass that has long been used as an abrasive in cleaning, polishing, and scouring compounds.

Pumice is formed when volcanoes erupt explosively. It comes from the same kind of magma which would form granite or rhyolite, that is, a magma that contains lots of silica (quartz). Magma with lots of silica is usually thick and sticky.

Rocks that cool quickly, especially the outer layers of a flow, are primarily composed of glass particles and tiny mafic minerals. This is why the outer surface of a flow is black. The most abundant felsic mineral in lava rock is plagioclase feldspar, which gives the surfaces a waxy luster.

lava flow. Lava (magma that has erupted onto the Earth’s surface) is visually mesmerizing – as the molten rock flows downhill, lava exposed to the air cools to a deep black color, while the molten rock beneath glows bright orange.