1. Texture: This refers to the size, shape, and arrangement of the mineral crystals within the rock. Texture is determined by how quickly the magma or lava cooled and solidified:

* Intrusive (Plutonic) Rocks: These form when magma cools and solidifies slowly underground. Slow cooling allows for large crystals to form, resulting in a coarse-grained texture. Examples include granite and gabbro.

* Extrusive (Volcanic) Rocks: These form when lava cools and solidifies rapidly on the Earth's surface. Rapid cooling results in small crystals or even a glassy texture. Examples include basalt and rhyolite.

* Other textures: Igneous rocks can also have porphyritic texture (large crystals embedded in a fine-grained matrix), vesicular texture (holes from gas bubbles), or glassy texture.

2. Mineral Composition: This refers to the types and relative proportions of minerals present in the rock. The mineral composition is primarily determined by the chemical composition of the magma or lava from which it formed:

* Felsic Rocks: Rich in silica (SiO2), lighter in color, and tend to be more viscous (thick). Examples include granite and rhyolite.

* Mafic Rocks: Rich in magnesium (Mg) and iron (Fe), darker in color, and tend to be less viscous (thinner). Examples include basalt and gabbro.

* Intermediate Rocks: Have a composition between felsic and mafic, often with a grayish color. Examples include diorite and andesite.

* Ultramafic Rocks: Very low in silica and rich in magnesium and iron, very dark colored. Examples include peridotite and dunite.

So, in summary, the texture (related to cooling rate) and mineral composition (related to magma/lava composition) are the two primary factors used to classify igneous rocks.