A quartzose trachyte, an igneous rock often showing a fluidal structure.
A fine grained igneous rock composed essentially of orthoclase feldspar and quartz, or of rock glass having the same composition, with or without biotite, hornblende, or pyroxene. The fine grained equivalent of granite.
A silicic or felsic volcanic rock.
A fine-grained felsic volcanic rock with a similar composition to granite.
A fine-grained volcanic rock composed of quartz, K-feldspar and plagioclase. It is the extrusive equivalent of granite.
A volcanic rock containing more than 68% silica with a very high viscosity when in a molten state.
An extrusive igneous rock equivalent in composition to granite, in which the crystalline constituents are too small to be distinguished with the unaided eye.
A very light coloured volcanic rock with tiny crystals, that is gas-filled and explodes dangerously
rhyolite lava erupts at 700 to 850°C and contains a silica content of over 68 percent; it can also include the minerals quartz, feldspar, and biotite, which harden with a glasslike texture
A fine-grained, extrusive igneous rock of the same composition as granite. Rhyolite is formed when the parent magma solidifies rapidly and large mineral crystals do not have time to grow. Granite, a coarse grained or large crystal rock, is formed when the parent magma solidifies underground after a long cooling period which promotes the larger mineral crystal growth. Back
The fine-grained volcanic or extrusive rocks that is equivalent in composition to granite. Normally white, pink or gray in color.
a group of extrusive, felsic light-colored) igneous rocks which are typically porphyritic, with phenocrysts of quartz and/or orthoclase feldspar in a cryptocrystalline groundmass. The presence of phenocrysts indicates two stages (speeds) of cooling of the original magma.
Any of a group of felsic igneous rocks that are the extrusive equivalents of granite.
Fine grained, light coloured volcanic rock with a high proportion of quartz, equivalent in composition to granite.
A fine-grained light coloured volcanic rock, chemically identical to obsidian. Colour may range from white, through grey, and yellow to reddish-pink. Sometimes used as a raw material for lithic tools.
A group of extrusive (volcanic) igneous rocks with phenocrysts (visible crystals that grew out of the molten lava) of quartz and alkali feldspar in a glassy to cryptocrystalline (too small to be seen through an ordinary microscope) groundmass (matrix).
A volcanic rock similar in composition to granite and usually exhibiting flow lines.
very acid volcanic rock
volcanic rock chemically equivalent to granite Usually light colored, very fine-grained or glassy-looking. May have tiny visible crystals of quartz and/or feldspar dispersed in a glassy white, green, or pink groundmass.
A type of granite found in Colorado and used broadly around the State as a building material. It is perhaps one of the most common local masonry material used.
(geology): A dull, pink, streaky, igneous rock formed from minute glassy crystals of volcanic dust. In South Africa it is found only in the Lebombo Mountains, and is used for roads, concrete and insulation.
Igneous light colored rock (except obsidian). Components include Quartz and Feldspar.
Volcanic rock (or lava) that characteristically is light in color, contains 69% silica or more, and is rich in potassium and sodium.
A generally light-coloured volcanic rock, high in quartz content; rhyolite is the extrusive equivalent of granite.
The fine-grained volcanic or extrusive equivalent of granite, light brown to gray and compact. Fine grained, pink to dark purple felsic volcanic rock often with pink feldspar porphyry; fine grained equivalent to granite;
A type of volcanic rock that commonly erupts as pumice. Rhyolite typically contains about 75 percent silica and the stickiest lava known.
Fine-grained acidic volcanic rock mineralogically similar to granite, but possessing less quartz.
A fine-grained, extrusive igneous rock, which has the same chemical composition as granite.
the aphanitic equivalent of a granite thunder eggs form in rhyolitic rocks - Oregon & southeastern California
A light-colored, aphanitic volcanic rock composed largely of alkali feldspar crystals and free silica with minor amounts of ferromagnesian minerals.
the volcanic rock equivalent of granite, coarse grained crystals in a fine matrix
lava rich in silica (acid). Rhyolite is very viscous when erupted and often forms lava domes or very short thick lava flows.
a fine-grained extrusive igneous rock, often with a sugary texture, consisting of quartz, alkali feldspar and one or more ferromagnesian minerals
A group of extrusive igneous rocks, typically porphyritic and commonly exhibiting flow texture, with phenocrysts of quartz and alkali feldspar in a glassy to cryptocrystalline groundmass.
Highly felsic igneous volcanic rock, typically light in color; rough volcanic equivalent of granite.
a fine-grained extrusive volcanic rock, similar to granite in composition and usually exhibiting flow lines - BACK
volcanic leucocratic rock with a granitic chemical composition. Composed of quartz and feldspars phenocrysts, biotite flakes in a vitric groundmass recrystallized in paleovolcanic facies.
Rhyolite is a type of volcanic lava or rock that is usually light in color; it contains 69 percent silica and is high in potassium and sodium.
A volcanic rock compositionally similar to granite this is important in the genetic model for certain deposits, in this case, the Eskay Creek deposit.
A felsic volcanic rock; the extrusive equivalent of granite
A type of highly viscous magma with high silica content, it is found as pumice, ignimbrite, lava or obsidian. Rhyolite is also the name given to the volcanic rock formed from rhyolitic lava.
silica-rich volcanic rock (normally consisting of orthoclase feldspar and quartz)
Fine-grained extrusive igneous rock, commonly with phenocrysts of quartz and feldspar in a glassy groundmass.
One of a group of extrusive igneous rocks commonly showing flow textures, the extrusive equivalent of a granite; The chemical symbol for sulphur;
A pale coloured igneous rock of fine grain size, which is relatively rich in silicates such as quartz, feldspar and mica. Most rhyolites form as lavas, and may show complex flow banding.
a volcanic rock containing quartz and alkalil feldspar, with texture often showing the lines of flow. [AHDOS
This page is about a volcanic rock. For the satellite system, see Rhyolite/Aquacade.