1. Precious Gemstones:
- Diamond: The hardest natural substance known, often referred to as the "King of Gems."
- Emerald: A vivid green gemstone from the Beryl family, highly prized for its color.
- Ruby: A deep red gemstone from the Corundum family, known for its brilliance.
- Sapphire: Any color of Corundum other than red, including blue, yellow, pink, and colorless varieties.
2. Semi-Precious Gemstones:
- Amethyst: A purple variety of Quartz.
- Citrine: A yellow variety of Quartz.
- Topaz: Available in various colors, including blue, yellow, brown, and pink.
- Garnet: Comes in different colors such as red, green, orange, and yellow.
- Peridot: A vibrant green gemstone known for its distinct color.
- Aquamarine: A pale blue to blue-green variety of Beryl.
- Tanzanite: A deep blue to violet-blue gemstone found primarily in Tanzania.
3. Other Gemstones:
In addition to the well-known gemstones mentioned above, there are numerous lesser-known gems that offer beauty and uniqueness:
- Agate: A banded Chalcedony with various color patterns.
- Aventurine: A green Quartz with distinctive sparkling inclusions.
- Carnelian: A reddish-orange variety of Chalcedony.
- Chrysoprase: A vibrant green Chalcedony.
- Hematite: A reddish-brown to black iron oxide mineral.
- Lapis Lazuli: An opaque blue gemstone with golden pyrite flecks.
- Moonstone: A variety of Feldspar that exhibits a milky iridescence.
- Opal: Known for its play of colors, including fire opal, black opal, and white opal.
- Pearl: An organic gem formed inside the shells of certain mollusks.
- Tourmaline: Comes in a wide range of colors, including green, pink, blue, and yellow.
It's worth noting that within these categories, there can be further distinctions based on color, clarity, cut, and carat weight, resulting in an even greater diversity of gemstone varieties available in the world.