White metal ring when tested was not gold or platinum but has 68 (1 missing) genuine 1.5 mm diamonds. There is a 925 inside the ring and a heart with the numbers 1 and 0 inside it. It appears to me to be art deco. I had never heard of genuine diamonds being set in silver until recently but the settings we’re not vintage, they were modern. Could it be palladium?.
Palladium usually has a PAL stamp on it. 925 usually indicates silver. You’re correct in that diamonds aren’t generally set in silver as it does not hold gems well.