Precious and semi-precious stones:
Precious: Includes diamonds, emeralds, rubies, and sapphires. These stones are more expensive due to their rarity, high hardness, and unique beauty.
Semi-precious stones include lapis lazuli, agate, amethyst, topaz, tourmaline, garnet, etc. The variety of colors and greater availability have made them less valuable than precious stones, but they are still very popular
