CE11 - Lecture 2 - Rocks and Minerals

Rock

A ______ is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized based in minerals included, chemical composition and its genesis.

Rocks

_______ are generally classified into three: Igneous, Sedimentary, and Metamorphic

Rock Formation

A mappable unit of rock consisting of an initially connected volume deposited in one interval of time.

A formation may contain an assortment of different kinds of rocks but there is a prevailing character in the mix of rocks.

The distinctive character of a formation may relate to the engineering properties.

Soils

______ are formed by weathering of rocks.

The ______ physical property is dictated primarily by the minerals that consists the weathered rock.

Weathering, erosion, transportation, and deposition

________ are process involved in breaking down rocks and transferring to another place until it settles in a place.

Outcrop

Any rock can be brought up to the surface and part of it becomes an ________ and be exposed to weathering and become sediments.

Sedimentary Rocks

_________ come from sediments which may come from any kind of rock. The rocks just need to be exposed and this usually means that these rocks are brought above surface.

Igneous rocks

___________ come from magma. Magma can form from metamorphic rocks (since it is only at great depths where metamorphic rocks form can you reach temperature to melt rocks naturally).

Minerals

_________ are naturally occurring inorganic compound with a definite composition. They make up rocks, although most of the rocks will have several different ________ in it. Only a small set of _______ are rock-forming: mostly silicates

Mineral Properties

Each mineral has a unique combination of diagnostic physical features.

Color

Mineral Property - some minerals may have variations of _______ so it is not a reliable way to describe minerals by itself

Streak

Mineral Property – color of the mineral in its powdered form

Luster

Mineral Properties - the way mineral reflects light (Metallic, Dull, Pearly, Vitreous (glassy))

Hardness

Mineral Properties - measures the ability to scratch or be scratched.

Mohs Scale of Hardness

___________ is used to determine how hard a mineral is by scratching it against reference minerals.

Cleavage

Mineral Properties - The way a mineral breaks along a plane easily and smoothly based on its lattice. The plane of breakage is called the _________ plane.

Fracture

Mineral Properties - The way a mineral breaks if there are no cleavage planes.

Density

Mineral Properties - Mass/Volume of a mineral. Specific weight (Weight/Volume) is simply the______ multiplied by g.

Mineral Identification

Identification of minerals contribute to identification of rocks and their properties.

Uses of Minerals

Since minerals are found in rocks, a lot of the characteristics of minerals matter in our usage of rocks.

Some minerals are mined to be used as additives or to be processed to make construction materials like gypsum, cement, and aggregates (sand and gravel used in concrete making).

Certain minerals that decay or become weak in certain conditions may be dangerous for certain sites/projects.

Mineral Formation via:

Precipitation, Metamorphism, Weathering, Organically

Mineral Formation

Most minerals forming the rocks are from the process of magma cooling. As magma rises, it cools, and minerals can crystallize.

Only small crystals are formed

If cooling is fast (minutes to years), minerals may not have time to become ordered, and __________

Larger crystals can form

If cooling is slow (decades to millions of years), higher level of ordering may be achieved, and ________

No crystals were formed

If cooling is too rapid (seconds), the rock will be glassy, meaning ___________

Mineral Groups

Minerals are grouped based on the predominant anion or anion complex.