Pumice is a textural rock and not a rock that is classified by mineralogy or chemistry. It is basically the solidified foam that forms from a lava rich in volatiles or gases. When the molten rock is effervescing to the point of forming a froth and then solidifies, pumice is the result. Pumice has numerous open spaces or vesicles in the form of round bubbles, linear tubes or irregular cavities. There is so much porosity in pumice that there is often more empty space than actual rock and in fact some pumice can float on water.
Some ocean related volcanoes have produced what are known as pumice rafts, which are actual floating mini islands made of rock. These pumice islands can exist for years floating along the ocean currents. Some may have been responsible for the distribution of island hopping animals and plants of the Pacific Ocean. Some pumice islands have been found with plants actually growing on them.
Pumice differs from obsidian in that obsidian is all glass and lacks the extensive vesicles of pumice. Most pumice is acidic/felsic in composition associated with rhyolitesince those lavas tend to have more volatiles, but intermediate and basic varieties are known to occur. Scoria is a much heavier ropey volcanic rock with larger but less prolific vesicles than pumice.
There are many uses for pumice as it is light weight, relatively hard and can have very sharp edges. It is used in the cosmetics industry as an exfoliating pad, scouring stones and as an additive in creams and lotions. Pumice's hardness makes it useful as an abrasive and its light weight gives it an advantage for use as large decorative rocks for landscaping. Its porous nature makes it a natural for filters.
sedimentary
Any with a density less than the fluid into which it is placed. Pumice is a volcanic rock that will sometimes float on water.pumice
Sedimentary rock can be formed from lithified sediments.
Floating rocks: pumice. Non-floating rocks: all but pumice. Pumice can float on water because its density is so low, due to trapped bubbles of air which formed during its solidification from lava.
Any type of rock can turn into sedimentary rock through the process of weathering and erosion. This involves the breaking down of existing rocks into sediments, which are then compacted and cemented together to form new sedimentary rock.
ORGANIC SEDIMENTARY ROCK`s : Is a type of sedimentary rock because sedimentary rock has three types of sedimentary rock called clastic , chemical , and organic sedimentary rock so yes ORGANIC SEDIMENTARY ROCK is a type of sedimentary rock..........................................
It is an igneous (volcanic rock).
sedimentary.
Metamorphic rock, if buried deep enough.
A "metamorphic" rock.
sedimentary
Pumice
sedimentary rock
sedimentary rock.
Pumice.
Any with a density less than the fluid into which it is placed. Pumice is a volcanic rock that will sometimes float on water.pumice
Sedimentary rock can be formed from lithified sediments.