What tolerance should I expect on calibrated stones?

Face-up dimensions are normally held closely; depth varies far more unless you specify it. State a maximum depth in your requirement and it becomes part of the specification rather than a surprise.

Can you match a repeat order to a previous delivery?

Yes, and it is the right way to run a repeating programme. Keep a few stones from the first delivery as a physical reference — colour language drifts between people and over time, a retained stone does not.

What is the smallest size you can supply?

Round melee from around 1.0 mm in the species that calibrate at that scale. Send the size, count and colour band and we will tell you what is realistic.

Format

Calibrated Gemstones

Stones cut to standard millimetre dimensions, so they drop into existing settings and repeat across production runs.

Send Your Requirement Browse Gemstones

Spinels spaced on a white ground in lavender, steel grey, mauve and pink, mostly round brilliants with a pink pear-cut stone at the centre.

What calibration actually guarantees

A calibrated stone is cut to a standard face-up dimension rather than to maximum weight. That is what lets a manufacturer buy a setting and a stone separately and have them fit.

Standard commercial steps run from about 1.0 mm for round melee in quarter-millimetre increments, then in half-millimetre steps for ovals and cushions from roughly 4 × 3 mm upward.

Face-up dimensions are the easy half. Depth is where orders go wrong, because cutters retain weight by leaving stones deep and stones are sold by the carat. If you do not state a maximum depth, expect the deep end of the range.

What to send us

A calibrated requirement that can be filled without a round trip contains:

Species, variety and colour band — with a reference image
Shape and face-up dimensions in millimetres
Maximum depth, and a minimum if the mount needs one
Girdle requirement, if you are setting pavé or channel
Piece count, and whether the order repeats
Quality stated as a floor, not an average
Treatment tolerance

Which species calibrate well

Availability varies sharply by species, and it is worth knowing before you design around one. Sapphire, ruby, aquamarine, peridot, zircon and rhodolite garnet calibrate reliably and are available in quantity.

Emerald calibrates with wider depth tolerances, because cutters lose more weight working around fractures. Spinel and tsavorite do not calibrate at scale — for those, tell us the quantity early, because it determines whether the requirement is realistic at all.

Repeat programmes

A repeating order carries an obligation the first order does not: the second delivery has to match the first. The reliable way to handle that is a retained reference — keep stones from the first run and have subsequent runs matched against them rather than against a written description.

Tell us at the outset that an order repeats. It changes what we will commit to and what we hold back.

Buyer questions