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, each field explained — what it means, and why it must appear on the spec.
Metal: 18K gold and Au750
18K gold is an alloy that is 75% pure gold; Au750 is the same standard written another way — 750 parts gold per thousand. The remaining 25% determines the color: more copper leans rose, palladium leans white. Writing “18K yellow gold (Au750)” on a spec fixes fineness, color and density at once — all three bear directly on production.
Center stone: species, weight and dimensions
A center-stone spec states both weight and dimensions — for example “oval sapphire, 1.5 carats (7×5 mm)”. The carat is a unit of weight, one carat being 0.2 grams; millimeters are geometry. Seats are cut in millimeters and value is priced in carats, and neither can be derived from the other — so both are required.
Side stones and pavé
Side stones are the smaller stones beyond the center, usually specified by total weight and setting — for example “round diamonds, 0.3 carats, pavé”. Pavé sets small stones edge to edge, held by tiny metal beads, paving a continuous field of light — and its demands on stone spacing and hole precision are the highest of any setting.
Settings: prongs and halo
A prong setting grips the stone with metal claws — four prongs admit the most light, six hold more securely. A halo rings the center stone with small diamonds, visually enlarging it. One design may combine several settings: “four-prong, double halo” means the center stone held by four prongs, wrapped by two rows of side stones.
Ring size and gold weight
Ring size is the ring's dimension; in Hong Kong's numbering, each size maps to an inner diameter — size 14 is 17.3 mm. Gold weight is the finished piece's weight in gold, derived from model volume times alloy density; it drives material cost and the weight felt on the hand. Specs mark gold weight as approximate because finishing and polishing shave off a small loss.