Platinum was first used by the ancient Egyptians around three thousand years ago, it is only mined in less than ten locations around the world, the largest deposits are in Russia and South America. Greyish white, heavy and durable are all attributes of platinum, it is an excellent choice for heirloom jewelry.
Platinum is very dense and has a melting point of 3214.9 °F, this is partially because the density is higher than most metals.
Gold is a warm and rich medium that has been valued from the earliest times in recorded history and used for centuries to create heirloom jewelry. It’s durability and versatility in color makes it an excellent choice for custom jewelry. Naturally yellow in color, gold is also available in white, green, and rose.
Pure gold is very soft so it must be alloyed with other metals to give it strength to use for jewelry and create various colors. 24k gold is 99.9% pure solid gold, 18k gold is 75% solid gold, 14K gold is 58.5% pure gold and 10k gold is 41.7% pure gold. The melting point of gold is 1947.52°F.
Sterling is metallic silver in color and is softer than gold. Record of silver dates back to ancient times, and even mentioned in Genesis. Slag dumps have been discovered in Asia and the islands of the Aegean Sea which indicates that people knew how to separate silver from lead dating back to 3000 B.C.
Silver will tarnish when exposed to ozone, sulphur and hydrogen. In recent years, silver has been alloyed with other metals so that is doesn’t tarnish as much. The melting point of silver is 1763.2°F, slightly lower than the melting point of gold. Sterling silver is alloyed with other metals to make it stronger to give it strength to use for jewelry. Sterling silver is 92.5% pure silver.
Links:
https://www.webelements.com/platinum/
https://www.webelements.com/silver/
https://www.webelements.com/gold/