Question

Which of the following is NOT one of the principal categories of rock-forming minerals?

1) halides
2) sulfides
3) oxides
4) native elements
5) peptides

Answer 1

Peptides are not a principal category of rock-forming minerals; the principal categories include halides, sulfides, oxides, and native elements.

Step-by-step explanation:

The principal categories of rock-forming minerals include halides, sulfides, oxides, and native elements.

These categories cover a vast majority of minerals found within the Earth's crust and serve as fundamental components of various rock types.

Among options 1) halides, 2) sulfides, 3) oxides, 4) native elements, and 5) peptides, the one that is NOT considered a principal category of rock-forming minerals is peptides.

Peptides are organic compounds that are not minerals and therefore do not form rocks.

Examples of the principal categories can be seen in various ores and minerals, such as amethyst, cinnabar, azurite, and vanadinite, which illustrate the chemical composition and crystal structures that characterize mineral types.