Dark volcanic glass, usually of felsic composition.
A glassy igneous rock with a chemical composition equivalent to that of granite.
volcanic glass. Amorphous volcanic black material. More valuable varieties have sheen colors.
Glassy dark colored volcanic rock. Usually composed of rhyolite.
glass formed by volcanic eruptions
black, glossy volcanic rock. Often confused with onyx.
Natural glass produced by volcanic action. It is usually black or black-banded, and can be cut and polished and used as a gemstone.
A dark natural glass formed by the cooling of molten lava and used to make sharp tools and jewellery.
A hard, dark-colored glassy phase of lava.
acid or granitic glass; usually dark, but transparent in thin pieces
A black and glassy igneous rock, it forms when magma pours out of the earth slowly, but cools quickly.
Glassy type of Rhyolite igneous rock which is often transluscent. Brown to black.
Sometimes referred to as volcanic glass, this is a form of stone that has no internal blocky or crystalline structure. Consequently, it can be made to have an exceptionally sharp edge, though it is typically brittle.
A volcanic mineral that was the first form of natural glass used by humans. It is usually black, but it can also be very dark red or green; its splinters are often transparent or translucent.
(2) -- volcanic glass Sample Image (Lesson 8)
A volcanic glass which is one of the finest raw materials for the chipping of stone tools.
a dark, glassy volcanic rock.
a type of black stone (volcanic glass) found in the Western U.S.
a glass created by volcanoes. IGCB
a volcanic glass similar in composition to granite, usually dark but transparent in thin pieces
volcanic glass that can be worked into sharp-edged tools; is not present in the geology of the Bay Area and had to be obtained through travel or trade; nearest sources are Napa and Sonoma counties.
Obsidian is volcanic glass. This blackish stone has been used for grounding and shielding. It promotes reflection and helps to sooth the temper. As a healing stone it transforms negative vibrations within an environment. And as a healing stone brings clarity to both the healer and the one being healed. Obsidian aids in healing grief. Vibrates to the #1.
Very hard volcanic glass used for tools. It can be dated by measurement of thickness of its hydration layer on surface
A black volcanic glass of rhyolite or dacite composition.
A dense, usually black, volcanic glass.
A super-chilled igneous rock, black in colour and glassy in appearance. Fractures conchoidally. Often formed due to contact with cold seawater as the silicate minerals cool almost immediately, restricting mineral growth. Can also be called volcanic glass... More
A jet-black volcanic glass, usually of rhyolitic composition, formed by rapid cooling of viscous lava.
An igneous rock consisting of a solid mass of volcanic glass.
A black or dark-colored volcanic glass, usually of rhyolite composition, characterized by conchoidal (curved) fractures.
Black to dark-colored volcanic glass, similar in composition to rhyolite.
An acid resistant, lustrous volcanic glass, usually black or banded and displaying curved shiny surfaces when fractured.
a black or banded hard volcanic glass that displays shiny curved surfaces when fractured and is formed by the rapid cooling of lava - BACK
Volcanic glass which can be chipped to make an extremely sharp edged tool. It was often used at Çatalhöyük in making stone (lithic) tools.
This comes from the name of a man, Obsius, who was supposed to have found this rock in Ethiopia thousands of years ago. Obsidian is ancient volcanic glass and was once widely used for arrowheads.
Obsidian is a natural volcanic glass that is often formed when lava comes in contact with water and is quickly cooled. It can be dark green or black depending on the trace minerals present, and may have inclusions (See Snowflake Obsidian). Obsidian is similar to quartz chemically, but is lacking a crystalline structure and some of the electrical properties of quartz.
It is projective and is used for grounding and divination. Obsidian is naturally occurring glass: it is simply lava that cooled so fast that the minerals contained within didn't have time to form. The ancient Aztecs fashioned it into mirrors. It also was popular for fashioning stone knives and spear heads. In Mexico obsidian is still fashioned for scrying tools. For some, the blackness of the stone allows easier contact with the subconscious mind.
(1601, from obsianus lapis meaning stone of Obsius, its supposed discoverer) Obsidian is lustrous volcanic glass formed in the flaming core of the earth and transported to the surface in volcanic eruptions. Also called lava glass, obsidian is fairly fragile. Although the colour range and related names are varied, it is generally deep black, black with white flecks (snowflake obsidian), dark green or brown.
Rock. Volcanic rock that cools very quickly to form glass. Usually black. Used by native peoples to make arrowheads.
Glass that is formed by lava that rapidly cools. Name is derived from its discovery by a Roman named Obsius.
(ob-sid'-i-an) A black or dark-colored volcanic glass, usually of granitic or rhyolitic composition, characterized by conchoidal (shell-shaped) fracture, produced by quick cooling of lava on or near the Earth's surface.
Volcanic glass. Usually black, but known also to be red, green, and brown.
Obsidian (also called Apache tears) is a volcanic glass that is usually black, but is occasionally red, brown, gray, green (rare), dark with "snowflakes," or even clear. This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive. Obsidian is formed when viscous lava (from volcanos) cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35. The pin above is Mahogany (brown) obsidian.
a hard, dark, glassy rock that is formed when rhyolitic lava cools; volcanic glass. [AHDOS
Is a natural glass that is formed from lava that cooled too quickly to crystallize.
