A small bridal shop in Columbus ordered 50 round brilliant moissanites at 6.5 mm in January and was fully restocked by March. The same order included ten stones at 9 mm that are still in the tray in October. The shop did not misread demand for moissanite; it misread which millimeter brackets move. Round brilliant is the workhorse cut, but stocking it at the wrong sizes ties up cash and leaves the bench empty when the customer actually walks in.
This piece walks through the millimeter brackets that wholesalers should hold in stock, the brackets to order to cut, and the numbers behind each. It assumes a US independent retail or assembly buyer buying loose stones to set in rings, studs, and pendants.
The size ladder wholesalers actually move
Round brilliant moissanite is sold by millimeter, not by carat equivalent, because the carat weight of a 6.5 mm moissanite runs about 0.8–0.9 ct equivalent versus a 1.0 ct diamond at the same diameter. The specific gravity of moissanite is about 3.22 against 3.52 for diamond, so stones of equal diameter weigh less. Retail customers shop by the look of the face-up size, which is why the millimeter ladder matters more than the carat label. GIA's 4Cs education on carat weight explains how diameter and weight relate, and it is a useful handout to give retail accounts who are still learning the difference.
The brackets that move fastest, in order:
- 5.0 mm (0.4–0.5 ct equiv) — studs, three-stone side stones, and men's bands. Steady reorder, never a hero SKU but never dead.
- 5.5 mm (0.5–0.6 ct equiv) — mid-price solitaire and pendant. The highest-volume bracket for shops under $500 retail.
- 6.0 mm (0.7–0.8 ct equiv) — the entry engagement size. First-time buyers compare this against a 0.75 ct diamond.
- 6.5 mm (0.9–1.0 ct equiv) — the single best-selling bracket. Most bridal accounts want at least four to six stones in this size on the shelf at all times.
- 7.0 mm (1.1–1.2 ct equiv) — the upgrade buyer. Moves a little slower than 6.5 but at a healthier margin.
- 8.0 mm (1.7–2.0 ct equiv) — the luxury bracket. Stock one or two, not ten.
- 9.0 mm and above (2.5 ct+ equiv) — cut to order. Holding five of these on the shelf ties up cash for six months.
Our piece on 1 ct to 5 ct stocking ranges goes deeper on the larger brackets, and carat weight pricing tiers shows how the per-carat price steps up as diameter grows.
Color and clarity mix within each size
Within 6.5 mm, the D-F VVS bracket outsells G-H VS by roughly three to one in bridal, but G-H VS moves faster in stud earring jobs. The reason is that studs are viewed at arm's length where a faint warm tint reads as white, while an engagement ring is compared face-up next to the customer's existing white-gold band. We cover this split in D-F vs G-H bulk stock.
For stock planning, hold 70% D-F and 30% G-H in the 5.5–7.0 mm brackets. Below 5.0 mm, color is almost invisible and the cheaper grade is fine. Above 8.0 mm, go back to 100% D-F because larger faces show body color more readily. If you are also buying fancy shapes, see oval face-up size guide for how oval diameter compares to round.
What to hold back for custom orders
Not every size deserves shelf space. The 3.0–4.0 mm range is used almost exclusively as side stones and should be ordered in matched sets, not singles. The 10 mm and above range is almost always a custom request; keep one sample in the display case but do not tie up working capital on depth. If a customer wants a 12 mm stone, lead time of seven to ten days is normal and acceptable.
How many 6.5 mm stones should a boutique hold at once?
For an independent shop doing four to six moissanite engagements a month, hold six to eight loose 6.5 mm D-F VVS stones plus two G-H VS. That covers two weeks of average turnover without overstocking.
Does round brilliant moissanite always come with a GRA certificate?
Most wholesale parcels from reputable suppliers ship with a GRA certificate per stone. Verify the report number on the GRA portal before resale; see bulk parcel GRA verification.
What diameter reads as a 1 ct diamond to most customers?
6.5 mm. A well-cut 6.5 mm round moissanite covers the same finger surface as a 1 ct round diamond and is the bracket most often sold as one-carat equivalent.
Should wholesalers stock melee sizes below 3 mm?
Only for setting accounts that buy in quantity. Individual boutiques rarely need 1.0–2.5 mm melee on hand; order it when a specific pavé job comes in.
Order from HOLYCOME. We stock round brilliant moissanite from 3.0 to 10.0 mm in D-F VVS and G-H VS, every stone with a GRA certificate, and we will split a parcel across the 5.5, 6.0, 6.5, and 7.0 mm brackets your shop actually sells. Apply for a wholesale account and request the current round-stone price list — minimum order 20 stones, mixed cuts and sizes allowed.
