A gemstone is a naturally occurring mineral, rock, or organic material that is cut and polished to enhance its beauty and is typically used in jewelry or decorative objects. Gemstones are valued for their rarity, color, brilliance, and durability. Some of the most famous gemstones include diamonds, rubies, sapphires, and emeralds.

There are two broad categories of gemstones:

1. Precious gemstones: These are the most valuable and sought after, including diamonds, rubies, sapphires, and emeralds.
2. Semi-precious gemstones: These are more common but still valued for their beauty, such as amethyst, garnet, turquoise, and aquamarine.

Gemstones can also be classified based on their origin:

• Mineral gemstones: Formed naturally within the Earth, such as quartz or topaz.
• Organic gemstones: Derived from living organisms, such as pearls, amber, and coral.

Gemstones are often cut into various shapes (e.g., round, oval, square) and polished to highlight their best features, such as color and brilliance.