This is Tiffany & Co.'s Half Eternity Ring. SA rank: Polished It is a beautiful item.
Brand name: Tiffany & Co.
Model name: Half Eternity
Size
Ring
Size: US 4.5 / EU 48
Width: 2 mm (0.08 in): 2.8 g
Accessories: None
Material: Pt950

Condition Guide:
S: Like new by the store's standards
SA: Almost unused, overall pristine
A: Excellent condition
AB: Great condition, minor signs of use
B: Good condition, signs of wear from normal use
C: Noticeable scratches, dirt, or signs of use
D: Heavily damaged or in need of repair
Item with difficulty being called C: