The density and weight of platinum make it more durable than other jewelry metals. 1 6 inch square (15.24 cm) platinum cubic weight 165 pounds (75 kg), which is equivalent to the weight of an ordinary man. Platinum is resistant to heat and acid, with a melting point as high as 3223 degrees Fahrenheit (1768 degrees Celsius). Platinum will not wear, and it can hold precious jewels stably and safely. Some world-famous gems are fixed on platinum bases, such as Coe-E-Noel diamonds and some jewels in the British crown. All precious metals leave scratches, including platinum. However, the scratches on platinum only move the metal and will not reduce its volume, while the scratches on gold will bring wear and reduce the volume of gold. If there are visible scratches on platinum, a qualified jeweler can re-polish it.