What are some interesting facts about obsidian?
- Obsidian Gemstone More information about obsidian stones
- Sagittarius Horoscope Obsidian is the lucky stone for those born under the zodiac sign of Sagittarius
- December Birthstone Turquoise is an alternate birthstone for those who born under the Sagittarius zodiac sign
- Gemstone Jewelry Store Do visit my store :)
What minerals can be found in Obsidian?
Warner Mountains/Modoc National Forest
- Pink Lady Mine. Popular for pink obsidian, a rare form of the mineral with a light red to bright pink coloration. ...
- Rainbow Mine. The only one of the four mines which can be accessed with most vehicles is the Rainbow Mine. ...
- Needles Mine. ...
- Middle Fork Davis Creek. ...
Is obsidian phaneritic or aphanitic?
Rondi: Everyone, meet Obsidian , an igneous rock that from melted rock, or magma. Obsidian is an “extrusive” rock, which means it is made from magma that erupted out of a volcano. If it was an igneous rock that formed from magma underground and did not erupt, it would have been called an “intrusive” rock.
Is Obsidian an igneous rock?
Obsidian is an igneous rock that forms when molten rock cools very rapidly. The result is a rock that cooled so fast, crystals did not get a chance to form. Obsidian is a volcanic glass with a smooth and uniform structure. Different varieties of obsidian rock get their names from their appearance.
Is obsidian mafic or felsic?
felsicThough obsidian is usually dark in color, similar to mafic rocks such as basalt, the composition of obsidian is extremely felsic.
Is obsidian intermediate or felsic?
Classification of Igneous RocksTEXTUREFelsicIntermediatePhaneriticGraniteDioriteAphaniticRhyoliteAndesiteVesicularPumiceScoriaGlassyObsidian1 more row
What type of igneous rock is obsidian?
extrusiveObsidian is an "extrusive” rock, which means it is made from magma that erupted out of a volcano. If it was an igneous rock that formed from magma underground and did not erupt, it would have been called an "intrusive" rock.
Which rock can be mafic felsic intermediate?
Igneous Rocks by CompositionCoarse-Grained TexturesFine-Grained TexturesPeridotite = UltramaficKomatiite (Ultramafic, but too rare to worry about at this point in your life)Gabbro = MaficBasalt = MaficDiorite = IntermediateAndesite = IntermediateGranite = FelsicRhyolite = Felsic
What composition is obsidian?
obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass.
Why is obsidian black and felsic?
Obsidian is a naturally occurring volcanic glass. It is formed during the eruption of felsic lavas, which are distinguished by having high concentrations of the chemical element silica. Because of their high silica content, felsic lavas do not behave like the mafic, or silica-poor, lavas we see on the island of Hawaii.
What are the properties of obsidian?
Obsidian is truth-enhancing. A strongly protective stone, it forms a shield against negativity. It blocks psychic attack and absorbs negative energies from the environment. Obsidian draws out mental stress and tension.
How do you identify obsidian rocks?
Examine the obsidian's general presence. It has a distinctive appearance of smooth glass. Obsidian is a frozen liquid that contains small amounts of mineral impurities. See the color Because pure obsidian is usually dark, on rare occasions it may also be almost white.
Is obsidian a rock or mineral?
Obsidian is an extrusive igneous rock. It is occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes.
Is obsidian ultramafic?
Obsidian is volcanic glass which erupts as a lava flow. Most obsidian is felsic in composition, yet typically it will have a very dark color (dark brown to black). Dunite has an ultramafic composition yet is apple green to yellowish green in color.
What are the intermediate mafic?
In a widely accepted silica-content classification scheme, rocks with more than 65 percent silica are called felsic; those with between 55 and 65 percent silica are intermediate; those with between 45 and 55 percent silica are mafic; and those with less than 45 percent are ultramafic.
Which rock has an intermediate composition?
Typical intermediate rocks include andesite, dacite and trachyandesite among volcanic rocks and diorite and granodiorite among plutonic rocks.
What is the difference between mafic and felsic?
Now comes the point of felsic or mafic. The classification of mafic and felsic is done based on the chemical composition of rocks. The rocks that are rich in feldspar and quartz are felsic whereas the rocks that are rich in magnesium and iron are mafic. Hence, technica
How does obsidian form?
Obsidian forms two ways: 1) very rapid cooling of lava, which prevents the formation of crystals; 2) cooling of high-viscosity lava, which prevents easy movement of atoms to form crystals. An example of obsidian that formed the first way is along the margins of basaltic lava flows at Kilaeua Volcano (Hawaii Hotspot, central Pacific Ocean). Examples of obsidian that formed the second way are shown below.
What is obsidian made of?
Obsidian rock is made up of felsic lava (rich in silicate) which is contrary to mafic. And mainly its igneous rock.
How is obsidian produced?
Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. So this is a felsic🤘
What is the left over material of an eruptive sequence?
Obsidian is the “left over” material of an eruptive sequence. High in silica. Felsic in composition. See: Mineral information, data and localities — Mindat. Also: Obsidian - Wikipedia
Where is obsidian found?
Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high viscosity and pol
What is the most common color of obsidian?
The most common color variation of obsidian is brownish-red, which occurs throughout the rock or as streaks in a black obsidian. Such rocks are called mahogany obsidians (see below). A rare variety is rainbow obsidian (see below).
What are intermediate rocks made of?
Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). There is little or no quartz. Felsic rocks are mostly feldspar (especially K-feldspar), at least 10% quartz, and less than 15% mafic minerals (biotite, hornblende).
Why do felsic magma erupt?
Because of their high viscosity, felsic magmas do not reach the surface as often as do intermediate or mafic magmas. However, because of its high gas content , when felsic magma does erupt, the eruption is the most violent.
Do felsic magma reach the surface?
Felsic magmas are much more viscous than the intermediate magmas. Because of their high viscosity, felsic magmas do not reach the surface as often as do intermediate or mafic magmas. However, because of its high gas content, when felsic magma does erupt, the eruption is the most violent.
What are the different types of igneous rocks?
Felsic, intermediate and mafic igneous rocks differ in their mineral composition. Felsic rocks are light in color and are composed of feldspars and silicates. Mafic rocks are darker and are composed of magnesium and iron. Intermediate rocks are composed of the minerals amphibole and feldspar and contain a combination of light and dark minerals.
What are the minerals in igneous rocks?
High temperature igneous rocks contain minerals higher in calcium, sodium, iron and magnesium. Ultramafic rocks are a fourth classification of igneous rock. These rocks are rare on the Earth's surface and contain low amounts of silica the minerals olivine, plagioclase feldspars and pyroxene.
What are intermediate rocks made of?
Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). There is little or no quartz. Felsic rocks are mostly feldspar (especially K-feldspar), at least 10% quartz, and less than 15% mafic minerals (biotite, hornblende).
Is obsidian a mineral?
It is sometimes classified as a mineraloid. Though obsidian is usually dark in color similar to mafic rocks such as basalt, obsidian's composition is extremely felsic. Obsidian consists mainly of SiO2 (silicon dioxide), usually 70% or more. Crystalline rocks with obsidian's composition include granite and rhyolite.
Is rhyolite a felsic rock?
Compilations of many rock analyses show that rhyolite and granite are felsic, with an average silica content of about 72 percent; syenite, diorite, and monzonite are intermediate, with an average silica content of 59 percent; gabbro and basalt are mafic, with an average silica content of 48 percent; and peridotite is.
