This amazing ring is not marked! Unbelievably, I couldn't find any information about it. The large stone appears to be Tanzanite and is so stunning! It appears to be surrounded (halo) by clear CZ stones. Not sure what they are either, but do not test as diamonds. Most likely rhodium plated as it has that look of brilliant shine. In pretty much perfect condition, it measures about a size 6. It may not be worth that much, but I'm keeping the price a bit high on it because I LOVE this ring! From a high end estate.