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Partially correct. Pumice forms from rapidly cooling lava containing volatiles (water and gas) and obsidian forms from rapidly cooling lava that doesn't contain volatiles. Bubbles from volatiles are frozen in place and cannot escape before the lava hardens forming pumice. Obsidian and pumice are sometimes found together although obsidian itself is relatively rare.
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What is a pumice source?
Pumice is produced in the lava from certain volcanic eruptions. It forms from gas-rich andesitic or rhyolitic lava and has so many gas bubbles that some pumice can float on water.
Pumice obsidian and scoria are kinds of?
volcanic rocks formed from different processes. Pumice is a light and porous rock formed from foamy lava, obsidian is a dark volcanic glass formed from quickly cooled lava, and scoria is a dark, vesicular rock formed from gas-rich lava.
What are Frothy volcanic rock are called?
Frothy volcanic rocks are called pumice. Pumice forms when lava with high gas content erupts from a volcano and cools rapidly, trapping gas bubbles within the rock, giving it a lightweight and porous appearance.
What is the size of grains in pumice?
Pumice normally doesn't have any grains at all. It would be very unusual for it to have grains. Just like Obsidian, Pumice is cooled too fast to have any grains in it. One of the biggest differences between them is that Pumice is cooled with pockets of air while Obsidian has a glassy look.
Is pumice andesitic?
Yes, pumice is typically an andesitic volcanic rock. It forms when frothy lava containing high amounts of gas vesicles cools rapidly and solidifies. This type of volcanic rock is commonly found in areas with explosive volcanic activity.
How is granite different from scoria pumice and obsidian?
Granite is an igneous rock that is coarse-grained and mainly composed of quartz, feldspar, and mica. Scoria and pumice are volcanic rocks with vesicular textures due to gas bubbles. Obsidian is a natural glass formed from rapidly cooling lava without crystallization.
Where does pumice form?
Pumice forms when volcanic lava with high gas content rapidly cools and solidifies, trapping bubbles of gas within the rock. This process creates a lightweight, porous stone that floats in water. Pumice is commonly found near volcanic areas and can be produced during explosive volcanic eruptions.
What is pumice and what causes pumice to be light enough to float on water?
Pumice has an extremely low density due to its vesicular nature. Obsidian is not characteristically vesicular like pumice and its density is greater. Therefore, in equally sized samples pumice is lighter.
What volcanic glass is caused by pockets of gas?
Pumice is a volcanic glass that is formed from frothy lava that traps gas as it cools, resulting in a light and porous rock.
What is a very light igneous rock honeycomed volcanic glass?
The very light, honeycombed volcanic glass is known as pumice. It forms when lava erupts from a volcano and cools rapidly, trapping gas bubbles inside its structure. Pumice is commonly used in skincare products and as an abrasive material.
What group of rock does pumice belong to?
Pumice is classified as an igneous rock. It forms when lava with high water and gas content is rapidly cooled and depressurized, causing it to solidify into a rock with a porous and frothy texture.
How are obsidian and pumice formed?
Pumice is formed by the rapid cooling of gas entrained (frothy) felsic lava which is erupted from volcanoes. If the amount of trapped gases in the lava is high, and cooled quickly enough to trap the bubbles of gas before they can escape, vesicular pumice will be formed, resulting in the only igneous rock that is able to float in water. Obsidian is formed from the extreme rapid cooling of lava.
