1. Composition: This refers to the minerals that make up the rock.

* Igneous Rocks: Formed from cooled and solidified magma or lava. Their composition depends on the magma's source and the way it cooled.

* Intrusive: Formed from magma that cooled slowly underground (e.g., granite, diorite).

* Extrusive: Formed from lava that cooled quickly on the surface (e.g., basalt, rhyolite).

* Sedimentary Rocks: Formed from the accumulation and cementation of sediments.

* Clastic: Composed of fragments of other rocks (e.g., sandstone, shale).

* Chemical: Formed from the precipitation of minerals from solution (e.g., limestone, rock salt).

* Organic: Formed from the accumulation of organic remains (e.g., coal, oil shale).

* Metamorphic Rocks: Formed from existing rocks that have been transformed by heat, pressure, and chemical reactions.

* Foliated: Have a layered or banded appearance due to pressure (e.g., slate, gneiss).

* Non-foliated: Lack a layered appearance (e.g., marble, quartzite).

2. Texture: This refers to the size, shape, and arrangement of the mineral grains within the rock.

* Grain Size: Can be fine-grained, coarse-grained, or porphyritic (containing larger crystals in a finer-grained matrix).

* Grain Shape: Can be rounded, angular, or elongated.

* Grain Arrangement: Can be random, aligned, or layered.

3. Structure: This refers to the overall arrangement of the rock, including features such as bedding, folds, and faults.

* Bedding: Layers in sedimentary rocks formed by the deposition of sediment.

* Folds: Bends in rock layers caused by compressional forces.

* Faults: Fractures in rocks where there has been movement.

These three properties, in combination, allow us to classify rocks into distinct groups and further understand their formation and history.