Home > Gemology > Gemstones > Rhyolite



Rhyolite is a relatively common volcanic rock. It is the chemical equivalent of granite. Although the two rock types have the same chemistry, rhyolite is extrusive and granite is intrusive. While granite has crystals that are generally easy to see, in rhyolite the crystals are often too small to see. This is due to the more rapid cooling of the rhyolite lava compared to granite's slower cooling magma.

In general, the slower a magma cools the larger the crystal size. Although crystals in rhyolite are usually hard to see, they are there, but as microscopic crystals often surrounded by a glassy matrix. If the lava fails to form crystals and is essentially all glass, then it is more correctly called an obsidian.

Rhyolite is found in volcanic arcs where crystal rocks have been subducted under continental crust and melted into a lighter magma rich in silica. Rhyolite contains over 70% silica or SiO2. This high silica content gives the rock its general light color, low density and a high viscosity to the lava.

Physical Properties:


Rhyolite Birthstone

Crystal System
Sio2, Silicon dioxide
Past life, third eye, higher heart

Sign of Rhyolite:Gemini

Rhyolitic lavas are often more explosive and slower moving than the less viscous basalt lavas such as those that erupt on the island of Hawaii. Rhyolite often is found with flow banding "frozen" into the rock. This lends to uses as decorative rocks and even ornamental stones for jewelry.

Usage:Self-esteem, acceptance, emotional release, challenging life circumstances, natural resistance, muscle tone, veins, rashes, skin disorders, infections, assimilation of B vitamins, stones, hardened tissue, electromagnetic and environmental pollution, radiation, stress, prolonged illness or hospitalization, circulation, digestive and sexual organs, balancing mineral content of the body.

Legend:Rhyolite facilitates change and brings about a deep state of meditation for inner and outer journeying. Accessing karmic wisdom, Rhyolite processes the past and integrates it with the present. This is an excellent stone to keep you anchored in the present moment rather than harking back to the past.

Occurrence: Rhyolites are known from all parts of the Earth and from all geologic ages. They are mostly confined, like granites, to the continents or their immediate margins, but they are not entirely lacking elsewhere. Small quantities of rhyolite have been described from oceanic islands remote from any continent.