A gem is a precious or semi-precious stone that is often cut and polished for use in jewelry. Common examples include diamonds, rubies, and sapphires. These stones are valued for their beauty, rarity, and durability, making them popular choices for adornment and investment. Minerals, on the other hand, are naturally occurring inorganic substances with a specific chemical composition and structure. They can be found in various forms, such as quartz, feldspar, and calcite. While some minerals are used to create gems, others have industrial applications or are used in everyday products.