Why isn't glass considered to be a mineral? (A)

A mineral is a naturally occurring, inorganic solid with a specific chemical composition and a definite crystalline structure.

Glass is an amorphous solid, meaning it does not have a definite crystalline structure. It is made by heating silica (silicon dioxide, SiO2) along with other substances like soda (sodium carbonate, Na2CO3), lime (calcium oxide, CaO), or lead oxide to high temperatures, and then cooling it quickly.

Let's compare the properties of glass with the criteria for being considered a mineral. 1. Naturally occurring: Glass is a man-made material, not naturally occurring. There are natural glasses like obsidian, but they're not considered minerals either. 2. Inorganic: Both glass and minerals are inorganic, so they meet this criterion. 3. Solid: Glass and minerals are both solids, so they also meet this criterion. 4. Specific chemical composition: Although glass has a chemical composition mainly based on silica, its composition can vary depending on the other substances added during its formation process. This doesn't fulfill the criterion of a specific chemical composition required for minerals. 5. Definite crystalline structure: Glass is an amorphous solid, meaning it lacks a definite crystalline structure, while minerals must have a crystalline structure. This is the main criterion that glass does not fulfill to be considered a mineral.

Based on the analysis, glass is not considered a mineral because it does not fulfill two of the necessary criteria - it is not naturally occurring, and it does not have a definite crystalline structure.