Ads
related to: snowflake obsidian stone minerals
Search results
Results from the WOW.Com Content Network
In some stones, the inclusion of small, white, radially clustered crystals (spherulites) of the mineral cristobalite in the black glass produce a blotchy or snowflake pattern (snowflake obsidian). Obsidian may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being ...
Its outer shape is spherical or lenticular. They vary in size from very small up to twelve feet in diameter depending on the age of the magma chamber. These rocks are usually found within obsidian or rhyolite lava flows. [2] Lavas low in feldspar minerals may produce a version known as snowflake obsidian.
Spherulites in rhyolitic ash, Hailstone Trail, Echo Canyon, Chiricahua Mountains, Arizona Spherulite markings on snowflake obsidian Photomicrograph of rhyolite, showing spherulitic texture (brown, between grey to white crystals) In petrology, spherulites (/ ˈ s f ɛr ʊ l aɪ t s, s f ɪər-/) are small, rounded bodies that commonly occur in ...
Cristobalite (/ k r ɪ ˈ s t oʊ b ə ˌ l aɪ t /) is a mineral polymorph of silica that is formed at very high temperatures. It has the same chemical formula as quartz, Si O 2, but a distinct crystal structure.
Apache tears are rounded pebbles of obsidian or "obsidianites" composed of black or dark-colored natural volcanic glass, usually of rhyolitic composition and bearing conchoidal fracture. Also known by the lithologic term marekanite , this variety of obsidian occurs as subrounded to subangular bodies up to about 2 in (51 mm) in diameter, often ...
Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is a glass made from the fused volcanic rock dust from Mount St. Helens and marketed as a gemstone. [ 1 ] [ 2 ] Helenite was first created accidentally after the eruption of Mount St. Helens in 1980 .
Obsidian is usually of rhyolitic composition, and it has been used for tools since prehistoric times. [34] Obsidian scalpels have been investigated for use in delicate surgery. [ 35 ] Pumice, also typically of rhyolitic composition, finds important uses as an abrasive , in concrete , [ 36 ] and as a soil amendment . [ 37 ]
A mineraloid is a naturally occurring substance that resembles a mineral, but does not demonstrate the crystallinity of a mineral. Mineraloid substances possess chemical compositions that vary beyond the generally accepted ranges for specific minerals, for example, obsidian is an amorphous glass and not a true crystal; lignite is derived from the decay of wood under extreme pressure ...
Ads
related to: snowflake obsidian stone minerals