An Art Deco ring in white gold. Tested as 18ct gold - no marks. C1920

Calibre set prisms of diamonds in an 18 ct gold channel. These linear cuts are designed to line up perfectly together with no gaps or metal between the stones giving the appearance of an invisible setting.A very popular style in that period but not much used these days as it is time consuming to produce. 

Slight unevenness to the channel edge. Have been racking my brains why but have realised the stones were not cut by computer - they could not get the accuracy we can so had to push the gold over to hold the stones and presumably needed to push by slightly different amounts depending on diamond size. Only noticeable on magnification.

Diamond height about 2mm. width 1.5mm, Number 12. Ct value about  1/3 carat. 

Size J (UK ) 4 5/8 ( US) sizeable Weight 4.55 gm

Identical one Size  J 1/2 (UK)  5 ( US) also sizeable 4.82 gm

Both have plain shanks which are quite thick and suitable for sizing. The rings have not , currently, been sized and were made to suit the smaller bone structure of ladies a century ago. The thickness of the shank is such that the rings are suitable for stretching rather than additional gold being required.