Emerald (noun)

1. A green precious stone, typically a variety of beryl.
2. A green color.
3. A green crystal or gemstone that is a variety of beryl and is colored green by small amounts of chromium and sometimes vanadium.

Origin:

Middle english: from old french esmeraude, via latin from greek smaragdos, probably via an unattested old iranian form.

Examples:

1. She wore an emerald ring.
2. The walls were painted in emerald green.
3. The emerald is the birthstone for May.
4. The emerald mines in Colombia have been known for centuries.
5. The statue was carved from a single emerald.