In the diamond manufacturing trade, fancies — sometimes called fancy rough — refers to rough diamond crystals whose external morphology departs from the idealised octahedron that underpins standard cutting calculations. The category encompasses macles (contact twins presenting a flattened, triangular outline), flats, cleavage fragments, and a broad range of irregular or distorted crystal forms. The term is used by manufacturers, rough dealers, and sorting-house graders to distinguish these goods from the two other principal rough categories: sawables (well-formed octahedra suited to sawing into two polished stones) and makeables (rounded dodecahedral or transitional crystals planned as single stones). Understanding where a parcel of rough sits within this three-way classification is the first step in any manufacturing decision.

Crystal Forms Included

The most commercially significant fancy rough is the macle, a contact twin in which two octahedral individuals share a (111) composition plane, producing a characteristically flat, triangular crystal with re-entrant angles at its edges. Macles have long been recognised as the natural precursors to marquise, pear, and heart-shaped polished diamonds, because their tabular geometry aligns well with the elongated or curved outlines of those cuts. Beyond macles, the fancies category includes:

• Flats — thin, plate-like crystals or cleavage pieces lacking the depth required for a standard round brilliant.
• Irregular or distorted octahedra — crystals whose faces are unequally developed, shifted by plastic deformation, or heavily etched by dissolution during their geological history.
• Aggregates and polycrystalline material — intergrown masses that resist straightforward planning.
• Cleavage fragments — pieces separated from larger crystals along the four octahedral cleavage planes, often with one or more flat, lustrous surfaces.

Planning and Weight Retention

The central challenge with fancy rough is that standard planning software and the experienced planner's intuition — both calibrated around octahedral geometry — must be substantially adapted. A macle, for instance, presents a twin boundary that can introduce strain and unpredictable cleavage behaviour during bruting and faceting. The planner must decide whether to work with the flat geometry (yielding a fancy-shaped stone) or to cleave or laser-cut through the twin plane in an attempt to recover two smaller but more conventional pieces, accepting the associated weight loss.

Weight retention from fancy rough is generally lower than from comparable-quality sawable or makeable goods. The irregular starting geometry forces greater sacrifices to achieve acceptable symmetry, proportions, and freedom from inclusions. This reduced yield is reflected in the price per carat that manufacturers are willing to pay for fancies at rough tenders and auctions, though exceptional macles of high colour and clarity — particularly those suited to large marquise or pear shapes — can command premiums when demand for fancy-shaped polished diamonds is strong.

Relationship to Fancy-Shaped Polished Diamonds

It is worth noting that the trade term fancies for rough is conceptually distinct from, though historically related to, the term fancy shapes for polished diamonds (any polished diamond that is not a round brilliant). The connection is not coincidental: the prevalence of macles and flat rough in early diamond production drove cutters to develop elongated and curved outline cuts — the rose cut, the briolette, and eventually the modern marquise and pear — that made efficient use of available geometry. Today, a manufacturer holding a parcel of macle rough will typically be targeting the marquise, pear, heart, or oval polished market, aligning rough supply with polished demand.

In the Trade

At the major rough-trading centres — historically Antwerp, and today also Mumbai, Surat, Dubai, and Botswana's Gaborone — fancies are sorted and priced as a distinct rough category. The major mining companies, including De Beers and Alrosa, include fancies in their standard rough assortments, and sightholders or tender participants must have the manufacturing capability to handle non-standard crystal forms. Smaller, specialist cutting operations sometimes focus specifically on fancy rough, developing proprietary planning approaches and maintaining relationships with polished buyers who consistently require fancy-shaped goods.

Graders sorting rough parcels evaluate fancies for colour, clarity, and — critically — the specific crystal form, since not all fancies are equally tractable. A clean, well-formed macle of fine colour is a very different manufacturing proposition from a heavily included, distorted flat, even if both fall under the same broad trade heading.

Further Reading

• GIA — Diamond Rough Planning
• GIA Gems & Gemology