1. 22-carat gold from which guinea coins were made
   "The antique jewellery was crafted from guinea gold"
    
2. Brass with enough copper to give it a reddish tint; used for plumbing pipe and other brass hardware and in cheap jewellery
   "The decorative fixtures were made of guinea gold to give them a warmer appearance";
   - red brass

Type of: atomic number 79, Au, brass, gold