Which is characteristic of a mineral?
a.
it must be crystalline and have an indefinite chemical composition.
b.
it must be amorphous and have an indefinite chemical composition.
c.
it must be amorphous and have a definite chemical composition.
d.
it must be crystalline and have a definite chemical composition.

Option (D)

Explanation:

The minerals are usually referred to as those substances that are crystalline in nature and are comprised of a specific type of chemical composition and proper internal structure.

These are very important because they combine with one another to form rocks, giving rise to the formation of either sedimentary, metamorphic or igneous rocks.

The different types of minerals are formed at different pressure and temperature condition. The minerals are characterized by the presence of both physical and chemical properties. Some of the physical properties of minerals include color, texture, hardness, fracture, and cleavage. Some of the chemical properties of minerals are the isotropic or anisotropic property of minerals, pleochroism, and extinction.

The study of minerals is known as mineralogy and it is widely used in the field of geology to understand the condition and factors that are responsible for its formation.

Hence, the correct answer is option (D).