Question

Which of the following cannot be classified as a mineral? a) Salt b) Ice c) Diamond d) Glass

Short answer

d) Glass

Step-by-step solution

Understand Mineral Definition

A mineral is a naturally occurring inorganic solid with a definite chemical structure and crystalline form, which means its atoms are arranged in an orderly repeating pattern.

Evaluate Salt

Salt, specifically rock salt (halite), is naturally occurring, inorganic, has a definite chemical formula (NaCl), and an ordered crystalline structure. Therefore, it is a mineral.

Evaluate Ice

Ice, when naturally occurring, is inorganic, has a definite chemical formula (H2O), and a crystalline structure. So, ice in nature qualifies as a mineral.

Evaluate Diamond

Diamond is naturally occurring, inorganic, has a definite chemical formula (C, pure carbon), and a crystalline lattice. Thus, it is considered a mineral.

Evaluate Glass

Glass is typically an amorphous solid, meaning it lacks a crystalline structure. It is not naturally occurring in its common form (like silicon dioxide glass) and does not meet all criteria to be classified as a mineral.

Key concepts

Inorganic Solid

Inorganic solids are defined as substances that are not composed of living materials. Unlike organic compounds, which contain carbon-hydrogen bonds, inorganic solids exclude such biological combinations. This means that minerals, which are usually considered inorganic, do not arise from organic, life-based processes. Instead, they originate from natural geologic processes.
Minerals are often found in geographical formations such as rocks and soil. Being inorganic also implies stability under normal environmental conditions. Both salt and ice are good examples of inorganic solids. They are not derived from any living organism and consist of specific chemical elements like sodium, chlorine, hydrogen, and oxygen.

• Not derived from living beings
• Composed of elements or compounds like NaCl or H2O
• Typically stable under natural conditions

Crystalline Structure

A crystalline structure is one of the key features that characterizes a mineral. It refers to the orderly and repeating arrangement of atoms in a substance. This structure gives rise to a crystal lattice that repeats in all directions, forming a definitive geometric shape.
The crystalline structure ensures that each mineral has a unique set of physical properties, such as cleavage, fracture, and optical characteristics. For instance, the crystalline structure of diamond, which is made of carbon atoms, gives it exceptional hardness and brilliance. Salt, another classic example, forms cubic crystals that are visible with what we commonly know as "table salt".

• Atoms arranged in repeating patterns
• Unique physical properties
• Examples: Diamond (carbon lattice), Salt (cubic crystals)

Chemical Formula

A chemical formula is vital for defining a mineral, as it describes the types and proportions of elements that make up the compound. Minerals have specific chemical formulas that imply a fixed ratio of elements bonded together. This is important because it determines the various properties and uses of the mineral.
For instance, salt has a simple chemical formula, NaCl, indicating it consists of one sodium atom for every chlorine atom. Similarly, ice has the formula H2O, representing two hydrogen atoms bonded to one oxygen atom. These formulas are consistent for naturally occurring minerals, providing insights into their structure and characteristics.

• Defines element types and ratios
• Unique to each mineral
• Examples: Salt (NaCl), Ice (H2O), Diamond (C)

Naturally Occurring Substances

Naturally occurring substances are those that are not synthesized or created by human intervention. For a substance to be classified as a mineral, it must form through natural processes, such as volcanic activity, crystallization from water solutions, or biological processes that leave mineral deposits.
This natural occurrence is crucial in differentiating minerals from man-made materials. Minerals like diamond are created deep within the Earth's mantle through high-pressure and high-temperature conditions. In contrast, glass doesn't typically occur naturally and is usually a product of human production processes. Therefore, unlike minerals, it often lacks the natural origin requirement.

• Formed by natural processes
• Essential criterion for minerals
• Examples: Diamonds (formed in Earth's mantle), Ice (formed by freezing water)