Mould Resin - Jewellery. Ovals, Rounds, Trapezoids, Squares and Polygons. 16 Cavity Jewellery Shapes Resin Mould. measures about 130mm x 130dmm. All cavities are approximately 7mm deep. The 2 squares are approximately 20mm x 20mm. The 2 Ovals are approximately 28mm x 22mm. The 2 larger Rounds are approximately 23mm. The 4 smaller Rounds are approximately 18mm The 2 Polygons are approximately 25mm x 20mm. The 2 Trapezoids are approximately 20mm x 25mm.The Rounded Polygons are approximately 26mm x 18mm. Measurements are approximate as it is very difficult with the moulded shapes to be precise.