The "glassy" igneous rock is called obsidian, and it occurs when the magma cools very rapidly.
Igneous rock usually appears with a well mixed texture without fossils, bands or layers, may contain vesicles (air bubbles or holes from trapped gases) and does not react with dilute acid.Igneous rocks can:Be glassy or frothy in appearance.Be felsic, intermediate, mafic, or ultramafic in nature.Be porous or full of bubbles.Have large crystal structure like granites.Have small crystal structure like basalts.Have a combination of large and small interlocked crystals.Be more dense than other rock types.Have an interlocking crystalline structure.Appear to be peppered with black specks.Be light enough to float (pumice).
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There are many places one might go to purchase mineral specimens. In addition to a museum shop, one might also try purchasing from the Amazon website.
A diamond. Actually, a diamond can be scratched my other minerals.
No, high pressure alone cannot change an igneous rock into sedimentary rock; however, the reverse is true. High pressure can change sedimentary rock into igneous rock.
If a rock has large crystals, it is an intrusive rock. Intrusive rocks form underneath the Earth's surface. Magma cools slowly so it has time to form large crystals. An example is granite, where you can see the crystals with your naked eye. Rocks that have small crystals are extrusive rocks. Extrusive rocks are ones that form from lava (blasted out of a volcano) so they cool very quickly, not allowing large crystals to form. An example is obsidian, where you cannot visibly see the small crystals; it just looks like one black, glassy rock.
These are igneous rocks that are too fine textured to an extent that there mineral grains or crystalline texture cannot be seen or distinguished with the necked or unaided eyes. They appear or occur as a whole single massive crystalline extrusive body of Igneous origin. Example is Obsidian.
it can only reflect off a minerals surface if it had the luster of glassy, metallic or pearly if the mineral is whats called dull the darkness of that mineral cannot obsorb the light like the brighter minerals can
Obsidian rocks are cooled very fast, and you cannot see the crystals in them.
Igneous rock usually appears with a well mixed texture without fossils, bands or layers, may contain vesicles (air bubbles or holes from trapped gases) and does not react with dilute acid.Igneous rocks can:Be glassy or frothy in appearance.Be felsic, intermediate, mafic, or ultramafic in nature.Be porous or full of bubbles.Have large crystal structure like granites.Have small crystal structure like basalts.Have a combination of large and small interlocked crystals.Be more dense than other rock types.Have an interlocking crystalline structure.Appear to be peppered with black specks.Be light enough to float (pumice).
An aphanite is a specific type of dark igneous rock with grain fine enough that individual crystals cannot be seen by the naked eye.
The texture is mostly dependent on the amount of time the magma or lava had to crystallize into a solid rock. Volcanic rock is formed from quickly cooling lava (also called extrusive igneous rock), and will have a fine-grained texture. Plutonic rock (also called intrusive igneous rock) is formed from slow cooling magma, and will exhibit visible crystals.
A mineral cannot be organic. A mineral cannot be made by or composed of life forms.
A mineral cannot be organic. A mineral cannot be made by or composed of life forms.
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Mass
A mineral must follow a certain criteria. It has to be naturally occurring, generally inorganic homogeneous solid with a crystalline structure and a definite (but not fixed) chemical composition. Water cannot be a mineral because it is a liquid. Honey cannot be a mineral because it is a liquid and is organic Oxygen cannot be a mineral because it is a gas. Teeth cannot be a mineral they are organic. Ice, however, can be a mineral if it is formed naturally. Ice forming on your windshield is a mineral but ice from an ice cube tray is not a mineral.