Diamond (noun)

1. A precious stone, typically a highly transparent, colorless crystal of diamond, prized as a gemstone.
2. A shape having four sides, each of which is a triangle and equal in size and shape.
3. A figure or representation of this shape, especially as used in heraldry.

Origin:

Late middle english diamant, from old french diamant, via old provençal from latin adamas, from greek, 'invincible, untamed, diamond'. the adjective (early 17th century) is from the noun.

Examples:

1. She was wearing a diamond ring on her finger.
2. The baseball field was laid out in the shape of a diamond.
3. The diamond pattern on the fabric added a touch of elegance to the dress.
4. The jeweler examined the diamond to determine its value and quality.
5. The team logo was a stylized diamond with the letter 'D' in the center.