Rhodium is among the rarest of metals and, being a member of the platinum group, it is also growing in popularity in the world of bullion investment and jewelry. In the cheaper tier of jewelry making it is associated with chemically applied thin plating to go over cheaper alloys underneath both to protect it from wear and corrosion as well as to give it a more upscale look. High end jewelry has been designed in solid rhodium to outrageous prices but despite demand the output has been small due to the considerable technical difficulties in working with this metal as it is brittle and requires very high temperatures. Most commercially available rhodium is hot pressed sintered powder which comes close, but does not quite achieve, the full density of the metal.