Vintage c1950s Japan Faux Pearl Double Strand Necklace w/ floral decored Squares

Vintage c1950s Japan Faux Pearl Double Strand Necklace with Stone/Ceramic? Squares. The necklace is in fine used condition. It looks well taken care off. No damage or other flaws visible. The 3 squares look like decorated and glossy glazed natural stones. They have like grooves I try to get on the pictures and they are all slightly different. The middle one has a large groove but the decor goes over it. One other looks like it has a signature on the side. We are not 100% sure about the material. Please check the pictures as they are part  of the description. The squares have the same design on front and back. There is a photo of each side. On the gold tone clasp it says "Japan". Lovely special elegant and eye-catching item! Great special gift! Length app. 17.5" from one end to other including clasp. The squares are app. 1.5" x 1.5" x H 0.5". Weight of item app. 2.3 oz..