Granite: a fine to coarse-grained, igneous rock formed by volcanic action consisting of quartz, feldspar, and mica, with accessory minerals. Granite-type rocks included those of similar texture and origin.
Sandstone: A sedimentary rock formed from years of compacting pressure, composed of primarily silica based sands and mineral particles. It is known for its glamorous sedimentary layers, or ‘grain’ look, sometimes appearing to be wood-like. Most sandstone is relatively soft, allowing for detailed cutting and carving, though in some uses its softness is not recommended.
Flagstone: thin slabs of stone used for flagging or paving walks, driveways, patios, etc. It is generally fine-grained sandstone, bluestone, quartzite or slate, but thin slabs of other stones may be used.
Basalt: Often called “lava rock”, basalt is an igneous rock formed from rapid cooling of magnesium and iron rich lava. More than 90% of all volcanic rock on Earth is basalt and it is also found on the moon. Most is shades of grey or black, and it has excellent thermal insulation values.