Platinum art deco engagement ring

Some information:
  Style:Art Deco.
  Style specifics: Abstract motives and geometrical forms are quite typical for the Art Deco period.
  Source of inspiration:: Japanese art (see the decoration at the side of the ring).
  Material: Platinum.
  Diamonds: One cushion cut or old mine brilliant cut diamond with an estimated weight of approx. 0.49 crt. (apprixmate color G/H and clarity vs) Note: All diamond weights, color grades and clarity are approximate since the stones were not removed from their mounts to preserve the integrity of the setting.
  Birthstones: Diamond is the birthstone (or month stone) for April.
  Hallmarks: Illegible remains.
  Weight: 2.40 gram (1.54 dwt).
  Ring size Continental: 48 & 15½ , Size US 4½ , Size UK: I .
  Resizing: Free resizing (only for extreme resizing we have to charge).

     An engagement ring is a finger ring of no generally accepted form that is given by a man to his fiancée as a token of marriage engagement, in the manner of the earlier betrothal ring, and indistinguishable in form or style. In recent years such rings have normally been set with a gemstone, usually a diamond (or any stone other than the ill-reputed opal), as a solitaire, of varying sizes, cuts, styles, and cost, but in the 19th century some were set with a pearl. In the same century the custom arose in England of separate engagement ring and wedding ring, and in very recent years such rings have sometimes been made en suite as a matching pair of similar style. In recent years, antique gemstone engagement rings are rapidly gaining in popularity.