Gemstone

In the jewelry business, gemstones are classified into precious stones and semi-precious stones.

Only four types of gemstones are considered precious stones by the jewelry industry:

• Diamond
• Ruby
• Sapphire?
• Emerald

Semi-precious stones include:

• Topaz?
• Aquamarine?
• Amethyst
• Citrine?
• Alexandrite
• Garnet?
• Spinel?
• Tanzanite?
• Tourmaline?
• Zircon?

some unnatural stones used as gem stones include:

• [Cubic zirconia]?
• [Lab created Ruby, Sapphire and Emerald]?