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because of the history that has been put into them such as a hawiian finding a rock and taking it home cleaning it and polishing it.
or there were items thron into a volcano before eruption such as dimonds then when the volcanos erupted the magma and items were mixed it a hardend together
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoOnly one Igneous rock is shiny that's obsidian and the reason its shiny is because since its extrusive rock it cools faster since Earths surface is cooler than the areas around the core so it cools fast so not enough crystals can form so it looks like black glass
Wiki User
∙ 12y agoThere is a black rock known as obsidian that is extruded from volcanoes. Obsidian is hard and brittle and that is why it fractures with very sharp edges. Obsidian was used as arrowheads, obsidian carvings, and even obsidian blades in the stone ages.
Wiki User
∙ 15y agoOnly certain igneous rocks are glassy--those that have experienced very rapid cooling from molten material.
Wiki User
∙ 11y agoIf a melted substance cools quickly it will be like glass ( lollipop candy) if it cools slowly then it will be more like crystals.
Wiki User
∙ 13y agoobsidian
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Some igneous rocks such as obsidian are glassy because they?
cool rapidly
What igneous rocks does not have a glassy texture?
basalt
Why does pumice have a lower density than other igneous rocks?
It is a glassy igneous rock, so there are holes in it. The holes make the rock less dense than other igneous rocks that are Not glassy.
What is the luster of igneous rock?
i think that igneous and metamorphic rocks uses luster because maybe they have it in them
Which igneous rocks would be formed by the fastest cooling of lava?
Glassy textured extrusive igneous rock, such as obsidian.
Some igneous rocks such as obsidian are glassy because they?
cool rapidly
Some extrusive igneous rocks such as obsidian are glassy because they?
cool rapidly
How some extrusive igneous rocks such as obsidian are glassy is because they?
Cool rapidly
What are rocks that have a glassy texture called?
Obsidian
What igneous rocks does not have a glassy texture?
basalt
Why does pumice have a lower density than other igneous rocks?
It is a glassy igneous rock, so there are holes in it. The holes make the rock less dense than other igneous rocks that are Not glassy.
What is the luster of igneous rock?
i think that igneous and metamorphic rocks uses luster because maybe they have it in them
Some extrusive igneous rocks such as obsidian are glassy because they are what?
They cool to quickly for crystals to form.
Which igneous rocks would be formed by the fastest cooling of lava?
Glassy textured extrusive igneous rock, such as obsidian.
What is the texture of Intrusive igneous rocks?
An igneous rock has two different textures. Extrusive rocks generally are smooth and glassy. Intrusive rocks are generally coarse
Do Glassy igneous rocks form when magma cools so slowly that mineral crystals cannot grow?
The "glassy" igneous rock is called obsidian, and it occurs when the magma cools very rapidly.
Why is a igneous rock appear smooth and glassy?
Some igneous rocks are very smooth and glassy (obsidian) while others have a very rough texture, such as the rocks used on the bottom of a propane gas grill. They are all formed from lava, but the glassy rocks cooled so fast that crystals did not have a chance to form. The rougher rocks cooled more slowly, allowing larger crystals to form--Slower cooling = larger crystals = rougher texture.
