Rocks & Minerals

Rock

A naturally occurring, inorganic solid material composed of one or more minerals or mineral matter

Mineral

A naturally occurring, inorganic solid element or compound defined by an ordered internal crystal structure, a characteristic chemical composition & specific physical properties

Igneous rocks

Rocks that form when hot molten rock cool and harden

Intrusive Igneous Rock

Form when magma ( hot molten rock deep underground ) cools slowly beneath the Earth, allowing large crystals to grow

Granite

Has specks of quartz, feldspar & mica

Gabbro

Dark grey - black with crystal sections

Extrusive Igneous Rock

Form when lava cools quickly creating glass like textures, small holes, or microscopic crystals

Pumice

Formed when gas-rich bubbly lava cools quickly resulting in small holes, and is so light that it’s floatable

Obsidian

Lava is cooled instantly resulting in a black, glassy texture

Basalt

Dark, dense rock which forms when low-silica, iron-rich magma erupts onto the surface and cools rapidly

Sedimentary rock

Rocks that form when layers of sediment are washed away by bodies of water and settle at the bottom, where over thousands of years it is compacted & cemented into new rock

Sandstone

Composed of sand grains

Limestone

Made from compacted shells, coral pieces, and calcite

Shale

Formed from the finest, microscoping clay & silt particles

Metamorphic rock

Rocks that form when existic rocks are subjected to extreme heat & pressure. These rocks don’t melt completely during their transformation.

Marble

When softer limestone is subjected to extreme heat & pressure. Soft enough to carve into statues.

Schist

Where visible mica flakes appear

Gneiss

Forms from granite, known for its squiggly light to dark stripes due to layers of mineral frequently being shaped during the transformation

Slate

Forms from shale subjected to extreme heat & pressure, resulting in perfectly flat, thin sheets ideal for roofing