Question

Minerals

Answer 1

• Silicon and oxygen are the most common constituents in most common minerals known as silicates.

• Positive and negative charges of cations and anions must cancel out for elements to combine to form minerals.

• A mineral is a naturally occurring, inorganic solid, with a definite chemical composition and uniform atomic structure, and is made up of elements.

• Minerals can be identified on the basis of features such as cleavage, color, hardness, and luster.

Figure . Quartz crystals form prisms; columns with pyramids at either end.

Elements combine to form thousands of minerals, mercifully there are relatively few minerals (~20) that are present in most rocks. Minerals share some key characteristics:

• Naturally occurring - not formed in a lab

• Inorganic - not formed by organisms

• A solid - not a liquid or gas

• Definite chemical composition – consistent chemical formula

• Uniform atomic structure – a three dimensional organization of atoms

• Made up of one or more elements

The most common minerals are composed of the most common elements. Silicon and oxygen make up over 70% of the continental crust by weight so it stands to reason that these elements would be present in many minerals. Minerals that contain both silicon and oxygen are known as silicates.

Just as we can use similar bricks to build many different structures, these basic building blocks, silicon and oxygen, can be joined together in a variety of ways in combination with other elements to form different silicate minerals such as quartz (Fig. 7) and feldspar.

Mineral Characteristics

Although there are thousands of minerals in Earth, there are only about 20 common minerals. The same mineral found in different parts of the world will always look the same and will have a characteristic crystal form and a consistent chemical formula. Minerals can be identified in rocks by a process of elimination. A variety of features can be used to identify specific minerals. Some of the most common are listed below.