Having been in the jewelry business over 40 years, and running a jewelry store most of that time. I believe jewelry should be at least 90% platinum to be able to be called simply, "platinum." Just as America's original gold coins were 90% gold, other jewelry with gold designations must be referred to as xx Karat Gold. People (consumers) expect platinum to be "pure." 90% should do it. Platinum was traditionally 90% Platinum and 10% Iridium. Now there are other alloys, but I believe anything less than 90% platinum should be given a full description. Thank you.