A diamond single stone ring

A diamond single stone ring, the modified brilliant-cut diamond estimated to weigh 0.80cts to the single-cut diamond-set foliate shoulders, the shank stamped '18ct' and possibly indistinctly plat 3.4g, size K1/2 Condition: In good overall condition, central diamond L/M, PK (small black mark on table visible to the naked eye), slight fluorescence,