Platinum jewellery should be labeled so you can tell how much platinum there is in the piece. Any jewellery that is not labeled platinum, plat, or pt. contains less than 50% pure platinum and shouldn’t be marketed as platinum. Platinum jewellery is rarely 100% pure platinum. Usually, the platinum is mixed with similar metals or non-precious base metals. Generally, the higher the percentage of pure platinum, the higher the value of the jewellery.