Latvian, J.R. & Co. Seal, Riga, Image & Found by MTC Cocoon Wim.
Found in the Oudenaarde region, East Flanders, Belgium, 20mm, 14.3?g.
Asterisk or flower head, J.R. & Co curving down / RIGA straight across // 1925
The company J R & Co has not been traced.
From Tanya Flow, "I'm not sure whether it is a valuable info (there's no mention of Riga but Germany), but the company's name matched very well - Porceain Marks & More, "Porzellanfabrik Joseph Rieber & Co. O.H.G. (1868 until 1923) ... Porzellanfabrik Joseph Rieber & Co. A.G. (1923 until 1971)."