100% pure gold is marked as “24k”. However, it is unusual to find a “24k” mark on a jewelry because pure gold is a soft metal and is more likely to scratch and bend. Gold in jewelry is therefore often mixed with other metals to make it more durable. “14k” it is the most common type of gold used in jewelry. According to the Austrian law, gold sellers should mark their products when the quality of gold is 14k, 18k or 24k.
14K consists of 58.5% gold and 41.5% other alloyed metals which help strengthening the gold piece. 18K consists of 75% gold and 25% other alloyed metals which help strengthening the gold piece.