Currently Platinum
Platiaum is the most expensive metal they use to make jewlery.
Technetium and Rhodium.
Because they were made of some good metal or something.....
because it is one of the most used metals
Iridium is the most strongest, rarest, densest, expensive, lightest metal ever known
Rhodium is the most expensive precious metal, valued for its extreme rarity and vital role in catalytic converters. Its high demand in the automotive industry drives its exceptional price and scarcity.
Rhodium is currently the most expensive metal commodity. It is used primarily in catalytic converters for vehicles and in the production of other chemicals. Its price can fluctuate significantly due to supply and demand dynamics in the market.
Steel in most cases. Aluminum in some very expensive cars.
gold and platnum and silver and white gold
Most foods are not 'fair trade' foods. Increasingly they are not fair trade and are more expensive. Given a choice people buy the cheapest offered.
No, they are often very impure, hence the lengthy and expensive refining processes for most.
Rhodium is pretty rare and very expensive. More rare than platinum.