Which one of the following is NOT true for minerals?
They have a specific, internal, crystalline structure.
They can be a solid, liquid.
They have a specific predictable chemical composition.
They can be identified by characteristic physical propertie
The Correct Answer And Explanation is:
Thought for 4 seconds
Answer:
The statement “They can be a solid, liquid.” is NOT true for minerals.
Explanation:
By definition, a mineral is a naturally occurring, inorganic, crystalline solid with a definite chemical composition and characteristic physical properties. Let’s examine each part of this definition in relation to the four statements:
- Specific, internal, crystalline structure
- True. All minerals possess an ordered arrangement of atoms in a repeating three-dimensional pattern. This internal lattice is what gives each mineral its unique crystal shape and many of its physical properties (e.g., cleavage, fracture, and crystal habit).
- They can be a solid, liquid
- False. By strict mineralogical definition, minerals are always solids. Liquids and gases lack a fixed crystal structure and do not meet the criteria for a mineral. For example, liquid water or magma, although composed of elements found in minerals, are not minerals themselves because they are not solids with crystalline structures. (Ice, however, is a solid crystalline form of H₂O and is classified as the mineral “ice.”)
- Specific predictable chemical composition
- True. Minerals have either a fixed chemical formula (e.g., halite is always NaCl) or a limited compositional range (e.g., plagioclase feldspar ranges from NaAlSi₃O₈ to CaAl₂Si₂O₈). This compositional constancy distinguishes minerals from rocks, which are aggregates of one or more minerals.
- Identified by characteristic physical properties
- True. Because each mineral’s internal structure and composition are consistent, minerals exhibit reproducible physical properties such as hardness (Mohs scale), specific gravity, luster (e.g., metallic, vitreous), streak color, cleavage (how they break), and crystal form. Geologists use these diagnostic properties in the field and laboratory to identify minerals.
In summary, the defining features of a mineral hinge on its being a solid with a crystalline structure, an inorganic origin, and a consistent chemistry. Thus, the claim that minerals “can be a solid, liquid” contradicts the fundamental requirement that minerals must be solid crystalline substances.