Melee & matched parcels.
“Melee” refers to the small stones, typically under a fifth of a carat, set in pavé, halos, channels and accents. They are bought not one at a time but by the parcel and for a designer or manufacturer the quiet challenge is consistency: a row of small emeralds only looks right if every stone shares the same green.
Most melee on the open market is mixed-origin, gathered from several sources and blended to reach a price. The result is a parcel that varies in hue and tone from stone to stone, visible the moment it is set side by side. Single-origin melee, colour-sorted and calibrated so that a whole parcel reads as one continuous green, is a materially different product and it is the harder one to supply.
For a house building to a standard, matched provenance melee removes the guesswork: the stones agree with each other and with the centre stone they surround.