Sedimentation is the process of allowing particles in suspension in water to settle out of the suspension under the effect of gravity. The particles that settle out from the suspension become sediment, and in water treatment is known as sludge.
Sediment is the loose sand, clay, silt and other. soil particles that settle at the bottom of a body of water. Sediment can come from soil erosion or from the decomposition of plants and animals. Wind, water and ice help carry these particles to rivers, lakes and streams.
Common sedimentary rocks include sandstone, limestone, and shale. These rocks often start as sediments carried in rivers and deposited in lakes and oceans. When buried, the sediments lose water and become cemented to form rock.
The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes.
Sediment examples include boulders, pebbles, cobbles, sand, silt, and clay. Boulders, pebbles, and cobbles are types of gravel and are the largest sizes of sediment. Clay represents the smallest size of sediment because each particle is exceeding fine.
When minerals grow, they become larger. Some minerals grow into different shapes and have many different colors. Other minerals have no distinct shapes and only one color. Not all crystals are minerals.
Minerals can be identified based on a number of properties. The properties most commonly used in identification of a mineral are colour, streak, lustre, hardness, crystal shape, cleavage, specific gravity and habit. Most of these can be assessed relatively easily even when a geologist is out in the field.
Some minerals are elements (e.g. graphite, diamond, sulfur), but most are compounds. A mineral is any naturally-occurring crystalline substance.
Talc Talc (1), the softest mineral on the Mohs scale has a hardness greater than gypsum (2) in the direction that is perpendicular to the cleavage.
Minerals can be identified by their color, luster, streak, cleavage, hardness, and even by their chemical composition. Using these properties is one way a Geologist defines and identifies what kind of mineral a specimen is. The museum has 6 wall spaces at the museum dedicated to these specific properties with examples.
