Cushion cut
Which Material, in a Cushion
This is the shape where moissanite is hardest to identify and easiest to spot, at the same time, for two different reasons. The faceting decides which one you get.
Written by the Mapple Gems workshop, Surat Β· Updated 30 August 2026
Short answer
Moissanite has two tells: doubled facet edges seen through the stone, and unusually strong coloured fire. A cushion's busy faceting hides the first almost completely β better than any other shape β and multiplies the second. So a crushed ice cushion in moissanite is very hard to distinguish from diamond, while a chunky cushion in moissanite throws large rainbow flashes that read as moissanite immediately. Choose the faceting according to which of those you want.
We have written about this choice in a step cut, where the answer is fairly clear-cut: an emerald's large open table displays moissanite's double refraction, so above two carats it is visible if you look. The cushion is the opposite case and considerably more interesting.
Why a cushion hides the doubling
Moissanite is doubly refractive: light entering the stone splits, and facet junctions viewed through it appear slightly doubled. Seeing that requires a clear, calm view through the stone at the facets below β which is exactly what a step cut provides and a cushion does not.
A cushion, especially a crushed ice one, is a mass of small facets throwing light in every direction. There is no calm window to look through and no clean facet edge held still long enough to examine. The doubling is physically present and practically invisible.
On this specific point, a crushed ice cushion is the most convincing shape you can buy moissanite in. That is a real, useful fact and one that very little buying advice mentions.
Why a cushion amplifies the fire
The other tell is dispersion β the splitting of white light into colour. Moissanite disperses light far more strongly than diamond does, which is why its flashes carry visible rainbow colour rather than mostly white.
Faceting decides how that reads. Many small facets produce many small flashes, so the colour arrives as a fine rainbow shimmer that most people find attractive and few identify as anything unusual. A few large facets produce a few large flashes, and a large flash of pure colour is unmistakable.
This is why a chunky-faceted moissanite cushion is the version people describe as looking like a disco ball. Nothing is wrong with the stone. The faceting is simply presenting the material's strongest characteristic at maximum size.
The four combinations
| Β | Crushed ice | Chunky |
|---|---|---|
| Moissanite | Fine rainbow shimmer. Very hard to identify. The most convincing option, and the cheapest | Large coloured flashes. Reads as moissanite to anyone paying attention. Spectacular if that is the intent |
| Lab grown diamond | Fine white shimmer. Forgiving on clarity and colour. Can go grey in low light | Large white and lightly coloured flashes. The classic antique cushion. Needs VS2 and G+ |
The two cells worth thinking hardest about are the diagonal. Crushed ice moissanite is the value option and the one nobody will question. Chunky lab grown diamond is the connoisseur's cushion and the most expensive of the four, because it needs both a better stone and better rough. The other two are perfectly good and land in between.
From our bench in Surat
Most of the "moissanite looks fake" complaints we hear trace back to one combination: a large stone, chunky faceting, and nobody having explained that the two together would produce that much colour. The customer wanted an antique cushion look and got a light show. The stone was fine and the expectation was never set.
So here is the concession, and it is a real one. Our cushion listings state neither the faceting style nor which material forgives which grades, which means a customer choosing a large chunky moissanite from our own pages has no way of knowing what is coming. Ask us before ordering a cushion moissanite above about two carats and we will tell you plainly which version you are looking at, and send video in ordinary room light rather than a lightbox.
The grades each material needs
Both materials follow the faceting rather than the shape. Crushed ice hides inclusions and colour, so a lab grown diamond can drop to SI1 and I comfortably, and moissanite's colour grade matters less. Chunky faceting hides nothing, so a diamond wants VS2 and G or better, and moissanite should be colourless grade β a grey or green cast in large facets is very visible. The grading conventions are in moissanite colour grades explained.
The other practical difference is weight. Moissanite is less dense than diamond, so it is sold by millimetre size with a diamond equivalent weight attached. A "2 carat" cushion moissanite measures like a two carat diamond but weighs less. Compare millimetres between listings, never carat against DEW.
What to specify
- Faceting style and material together β they are one decision, not two.
- Millimetres on both sides of any comparison, never carat against DEW.
- For moissanite above two carats: colourless grade, and video in ordinary room light.
- For lab grown diamond in chunky faceting: VS2 minimum, G+ in white metal.
- For either in crushed ice: take the lower grades the faceting permits and spend the saving on size.
- Depth percentage, because cushions of both materials are cut deep.
Keep reading
Crushed ice or chunky: how to tell before you buy
Frequently asked questions
Is a cushion cut good for moissanite?
A crushed ice cushion is arguably the best shape for it. The busy faceting conceals moissanite's doubled facet edges almost completely and breaks its strong dispersion into a fine rainbow shimmer rather than large coloured flashes. A chunky cushion does the opposite.
Why does my moissanite look like a disco ball?
Almost always a combination of large size and chunky faceting. Moissanite disperses light far more than diamond, and big facets deliver that colour in big flashes. The same material in crushed ice faceting produces a much finer, whiter shimmer. Nothing is wrong with the stone.
Can anyone tell a cushion moissanite from a diamond?
In crushed ice faceting, very few people could by eye β the usual visual tells are both suppressed by the facet pattern. In chunky faceting the coloured fire is a strong hint to anyone who knows what to look for. A jeweller with the right instrument can always tell, on any shape.
Does a 2 carat moissanite cushion equal a 2 carat diamond cushion?
In size, roughly yes; in weight, no. Moissanite is less dense, so it is sold by millimetre with a diamond equivalent weight. Compare the millimetre measurements between listings β that is the only figure that means the same thing for both materials.
Which combination is best value?
Crushed ice moissanite, comfortably. The faceting permits lower grades, conceals the material's tells, and the material itself costs a fraction of lab grown diamond at large sizes. The most expensive combination is a chunky lab grown diamond, which needs both better rough and better grades.
Ask before you order a large one
Above two carats the faceting decides how the stone reads. Tell us the look you want and we will tell you which combination gets you there.
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