when lava hardens, is it always either a basalt or a pumice? Can it harden into something else?

Answer 1

The type of rock formed by lava when it cools is determined by 1) the amount of volatiles in the lava (carbon dioxide, water, sulfur dioxide, and so on.
2) the composition of the lava (the abundances of silica, magnesium, iron, aluminum, calcium, and sodium, primarily)
3) the speed at which it cools.

A high amount of volatiles will cause the formation of vesicular basalt, or of pumice. Low volatiles will form massive a massive rock

Composition of the lava plays a huge role. Minerals will crystallize in a set pattern at a certain temperature and pressure. As these minerals form the various elements in the minerals are removed from the lava and are not available for other minerals. If, for example, all the silica is used up by the time the lava cools enough for quartz to form, then a basalt may form (if cooling is moderately rapid). If there is silica left over when it gets to the quartz temperature then quartz will form and the rock will be a rhyolite type or a granitic type rock (again, depending on the rate of cooling).

If a given lava cools very rapidly (as, for example where the lava spills into the ocean), then a volcanic glass may form, which is usually called obsidian. In obsidian crystals do not have the time to form before they harden, hence it is a glass. If the lava cools very slowly (underground, and called a magma if it doesn't spill onto the surface) granite or pyroxinites can form, sometimes with crystals that are as big as houses (really!). These rocks with the huge crystals are called pegmatites, and are commonly the source of rich mineral deposits, and mined for that purpose.

Answer 2

Pumice comes from pyroclastic flows that would be associated with an explosive type volcano like Mt.St.Helens. LAva coming from it also will not be basltic in nature.
Basalt comes from volcanoes such as the onese that make up Hawaii. Lava hardens into whatever it is made of. If it is a basaltic lava, it will harden into basalt. If it is a rhyolitic lava, it will harden into rhyolite.

Pumice is made from silica...the same stuff sand on a beach is made from. Silica under a microscope would be like very tiny, tiny pieces of sharp glass. That is basically what pumice and it comes from explosive volcanos.

Answer 3

Not sure where you found the terms basalt and pumice but they are just 2 outputs from volcanic activity. Basalt is fine grained heavy rock from lava that cools quickly on the earth's surface and originates from the thin oceanic crust. The terms basalt and pumice are very specific in terms of chemical composition and crystal structure and there are different names for every combination you can imagine so in other words it can harden into any number of different geologically termed rock.

Answer 4

There are many other things that lava can form into. Besides the typical geologic terms such as rhyolites, dacites, and obsidian, the lava could form into:

-A Giant robot if you had a mold large enough
-A profile of Our former president Bill Clinton and his favorite Aide Monica
-Large phallic towers if dripped off of a high precipice
-Large natural shaped bowls to catch snow melts so that monkeys can bathe in them
-Fluffy white clouds

Answer 5

Lava can also cool quickly into obsidian and cool slowly into rhyolite.

Answer 6

its pumice and it sucks its really sharp and makes stupid bubbles that people fall into and then that ****** lava burns you I hate it

Answer 7

sure, lots:
basalt,andesite, dacite, trachyte,latite,rhyolite,pumice, tuff and ignimbrite

Answer 8

If'n you rub it just right, it'll get hard, and spit in your eye.