Types of Rock

Extremely dense and hard (ex. Granite, Basalt)

Medium-density and relatively easy to work with (ex. Limestone, Sandstone)

any kind of stone that has been transformed by heat, pressure, or chemiccal actino into another type of stone (ex. Marble is altered limestone, Gneiss was once granite)

Metamorphic rock, medium to hard density (somewhere between shale and slate), dark red in color. Used for building. Usually cut into blocky, rectangular and square shapes.

Dense translucent or white fine-grained gypsum, slightly harder than soapstone and great for carving.

Dark-colored, fine-grained igneous rock formed by solidification of lava. Many types around the world. The Giants Causeway along coast of Northern Ireland is made of 37,000 basalt columns ranging from hexagons to polygons. Also in Pac. Northwest of US it's often used in water features and as water basins.

Rock-forming mineral that occurs mostly in igneous rocks, nearly 60% of earth's crust is made of it.

Metamorphic rock made of separate layers or bandings of materials, such as quartz, feldspar, and mica. Rustic surface quality, so good for building stone for mortared veneer and dry stone walls and commonly found on mountainous slopes, in fields, and in creek beds.

Often used in building and ornamental work. Heavy, coarse-grained igneous rock that contains quartz and feldspar. One of the hardest and most durable stones.

Bluish green to black mineral found in newly formed igneous rock.

Primarily made of calcium carbonate, derived from marine sediments, sedimentary stone. Good for carving and building. Varieties include oolitic, dolomitic, and carboniferous, each different based on texture and density.

Fine to coarse-grained crystalline rock, such as limestone, which has metamorphosed from its original form by heat and pressure.

Common mineral made primarily of Silica, a compound of silicon and oxygen. Present in many rocks and appears as speckling in granite and as bands in stones such as gneiss and hornblende.

Metamorphosed sandstone, extremely hard and nonporous. Contains up to 90% quartz. Considered a hard stone, but tends to shatter when struck with a hammer. Makes good border around garden beds, and larger pieces make good viewing stones.

Porous sedimentary stone with consistent crystalline structure. Medium density, good choice for mortared and dry-laid stonework. Easy to break and trim with hammer, suitable for stone carving.

Metamorphic rock made of flaky, relatively parallel layers of minerals, including iron and mica.

Soft rock made of layers of compacted, fine-grained clay, silt, or mud sediments.

Metamorphic rock was fine clay that metamorphosed by heat and pressure. Dense, fine-grained stone readily splits into thin, smooth pieces, commonly used for roofing, mortared paving, and kitchen countertops.

Soft, metamorphic rock made mostly of talc. Smooth, soapy feel, great for carving.