21K vs 18K Gold: The Difference
The question we hear most in the showroom. The answer depends on what the piece will do, not on which one is “better”.
Purity and colour
21K: purity 875, a clear yellow. 18K: purity 750, a lighter yellow — and more easily available in white and rose because the share of added metals is higher.
Hardness and stones
18K is harder. That is why it is the standard karat for set pieces: the prongs need enough hardness to keep the stone from falling out. Plain gold pieces sold by weight, without stones, are usually made in 21K.
Resale value
It is calculated on the weight of pure gold in the piece. The same weight in 21K contains more gold than in 18K — but set pieces are also valued for their stones.
Quick questions
Which is more expensive: 21K or 18K?
For the same weight, 21K contains more pure gold than 18K. But a piece's price also depends on its workmanship and any stones it has.
Which karat is better for a ring with stones?
Usually 18K, because its hardness keeps the prongs holding the stone from bending.