Avisilvers is an original brand in Nagoya, Japan.
This is a rare model that is no longer available for sale.
Size: Chain 45 cm, top 51 mm (including the shackle), weight 43 g.
According to measurements, the stone is 22 mm long, 11 mm wide, and about 8 mm deep. Using online formulas, it comes out to about 15-17 carats. This is a rough estimate.
The aqua zircon (starlight) is very beautiful, and the maximum width of the top is 51 mm, which makes the model quite large.
Perhaps because the stone is large, this piece makes a stronger impression than its size would suggest.