MineralsPrepared by;

Dion B. Orquia

Mineralogy (mineral = mineral, ology = the study of)- the study of minerals

Minerals can form from volcanic gases, sediment formation, oxidation, crystallization from magma, or deposition from a saline fluid.• The first minerals mined were flint and chert, which people fashioned

into weapons and cutting tools.

• As early as 3700 B.C, Egyptians began mining gold, silver and copper

• By 2200 B.C., humans discovered how to combine copper with tin to make bronze,

a tough, hard alloy

• The Bronze Age began its decline when the ability to extract iron from minerals

such as hematite was discovered

• By about 800 B.C., iron working technology had advanced to the point that

weapons and many everyday objects were made of iron rather than copper,

bronze, or wood.

• During the Middle Ages, mining of a variety of minerals was common throughout

Europe, and the impetus for the formal study of minerals was in place.

• Geologists define mineral as any naturally occurring inorganic solid that possesses an orderly crystalline structure and a well-defined chemical composition.

Characteristics of Minerals1. Naturally occurring2. Solid3. Orderly crystalline structure4. Well-defined chemical composition5. Generally inorganic

Orderly Crystalline Structure

Properties of MineralsPrimary physical properties – commonly used to identify hand samples

1. Luster 6. Hardness2. Color 7. Cleavage3. Streak 8. Fracture4. Crystal Shape (Habit) 9. Density or Specific Gravity5. Tenacity

Streak – color of powdered mineral

Crystal Shape (Habit) – characteristic shape of crystal

Tenacity – describes mineral’s toughness

Secondary (or special) properties – exhibited by a limited number of minerals

• Taste – ex. Halite, ordinary salt• Feels – ex. Talc and Graphite, both have distinctive feels: Talc feels soapy &

Graphite feels greasy• Smell – Ex. Streak of sulfur-bearing minerals smell like rotten egg.• Magnetism – ex. Magnetite, have high iron content and can be picked up with a

magnet• Double Refraction – some minerals exhibit special optical properties, Ex.

Transparent piece of Calcite is placed over printed material, the letters appear twice.• Chemical Reaction to Hydrochloric Acid – One very simple chemical test

involves placing a drop of dilute hydrochloric acid from a dropper bottle onto a freshly broken mineral surface. Certain minerals, called carbonates, will effervesce (fizz) as carbon dioxide gas is released. This test is especially useful in identifying the common carbonate mineral Calcite.

Mineral Groups

• Silicate Minerals – most abundant type of mineral, containing oxygen and silicon atoms

- have the same fundamental building block, the silicon-oxygen tetrahedron (tetra = four, hedra = a base), this structure consists of four oxygen atoms surrounding a much smaller silicon atom.

Nonsilicate Minerals – minerals that do not contain compounds of silicon and oxygen- Carbonates, oxides, sulfides, sulfates, native elements, halides

Rock cycle