It has a flat base and a convex upper surface. It is the time from when the Earth formed until simple life-forms evolved. Precipitation on Earth is is key in the water cycle . This time varies from culture to culture. This igneous rock is light and porous, containing a network of gas bubbles in volcanic glass and minerals.
Pumice can form from any types of magma, including basalt, andesite, dacite, and rhyolite.
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