How can you identify igneous rock?

Answer 1

Igneous rock usually appears with a well mixed texture without fossils, bands or layers, may contain vesicles (air bubbles or holes from trapped gases) and does not react with dilute acid.

Igneous rocks can:

• Be glassy or frothy in appearance.
• Be felsic, intermediate, mafic, or ultramafic in nature.
• Be porous or full of bubbles.
• Have large crystal structure like granites.
• Have small crystal structure like basalts.
• Have a combination of large and small interlocked crystals.
• Be more dense than other rock types.
• Have an interlocking crystalline structure.
• Appear to be peppered with black specks.
• Be light enough to float (pumice).

Answer 2

Igneous rocks typically have a crystalline texture due to the cooling and solidification of magma. They may also contain visible mineral grains, such as quartz or feldspar. Igneous rocks often have a glassy appearance if they cool rapidly, like obsidian. Furthermore, igneous rocks can have vesicles (small cavities) from gas bubbles that formed during cooling.

Answer 3

you simply look at the ROCK and predict if its extrusive igneous or Not

Answer 4

Intrusive igneous rock is composed of visible mineral crystals, possessing what is referred to as a phaneritic texture. This is evidence that slow cooling of magma occurred deep underground.

Answer 5

You identify by looking to see if there are any crystals that you can simply see. If you cannot see any crystals, that means that it is extrusive. If it is intrusive, you have to be able to see crystals.