A jewelry production spec, field by field: 18K Au750, pavé, halo, ring size
mulapis Research
An executable jewelry production spec states at least six fields: metal, center stone, side stones, setting, ring size and gold weight. Together they leave the factory with no questions to ask. Below, we explain what each field means and why workshops require it on the spec.
Metal: 18K gold and Au750
18K gold is 75% pure gold. Au750 expresses the same standard as 750 parts per thousand. The remaining 25% determines metal color, with copper producing rose tones and palladium creating white gold. Stating "18K yellow gold (Au750)" on a spec establishes fineness, color, and density together.
Center stone: species, weight and dimensions
A center-stone spec states both weight and millimeter dimensions, such as "oval sapphire, 1.5 carats (7×5 mm)". Carats measure weight (0.2 grams per carat), while millimeters define physical size. Jewelers cut stone seats in millimeters and price gems in carats, making both numbers essential.
Side stones and pavé
Side stones are secondary gems specified by total weight and setting style, such as "round diamonds, 0.3 carats, pavé". Pavé sets small stones edge to edge with tiny metal beads to create a continuous surface of sparkle. This requires precise stone spacing and drill depth.
Settings: prongs and halo
Prong settings hold stones with metal claws: four prongs admit maximum light, while six prongs offer greater security. A halo rings the center gem with smaller diamonds to enlarge its visual presence. Combining styles like a "four-prong double halo" means four prongs anchor the center stone inside two concentric diamond borders.
Ring size and gold weight
Ring size defines the inner band diameter. In Hong Kong sizing, size 14 corresponds to a 17.3 mm inner diameter. Gold weight comes from model volume multiplied by alloy density, determining material cost and hand-feel. Specifications list approximate gold weight because final polishing removes a small amount of metal.