A jeweler in Portland set a princess-cut moissanite in a four-prong solitaire and the stone came back three months later with a chip off the lower-left corner. The customer was not rough on the ring. The problem was the setting: the two prongs on the open corner were thin wire prongs that had bent out, leaving the corner unprotected. The moissanite itself had not fractured; it had been hit on an unsupported point. That failure is the classic princess cut durability question, and it is a setting problem more than a stone problem.
Moissanite scores 9.25 on the Mohs scale, second only to diamond (10) and tied with corundum. It is harder than ruby, sapphire, topaz, quartz, and every other colored gem sold in jewelry. The Wikipedia entry on moissanite lists the Mohs rating and the thermal and optical properties that make it suitable for everyday wear. The durability question is not whether moissanite survives daily life — it does — it is whether the princess cut's four sharp corners survive.
Where a princess cut can fail
The princess cut is a square modified brilliant with a pointed pavilion and four sharp right-angle corners on the crown. Those corners are the weak point. A direct impact on a corner chips moissanite the same way it chips a diamond princess — the corner is a thin edge of polished material with no facet geometry to absorb shock. The center of the table and the crown facets are much more resistant.
Wholesalers should tell retail buyers two things: (1) the stone itself is durable for everyday wear, and (2) the setting must cover the four corners. A bezel, a V-prong on each corner, or a halo of melee around the square all protect the corners. A thin four-prong setting with prongs only on the midpoints of the sides does not. We cover this in detail in corner protection settings.
How corner chips happen in real wear
The most common failure scenario is not a slam in a door. It is the slow accumulation of small impacts: setting the ring on a tile counter, catching the hand on a car door handle, knocking the ring against a desk edge. Each small impact on an unprotected corner micro-chips the stone. After a year, the chip is visible. The fix is usually a repolish that removes 0.1–0.2 mm from the corner — the stone survives, but it is no longer a perfect princess square.
For buyers stocking princess moissanite for everyday bands, this means two practical choices. Either sell the stone in a bezel or V-prong setting, or price the repair into the aftercare. If you are comparing princess against other square cuts, see radiant square vs rectangle for how the radiant's clipped corners reduce the chip risk, and cushion cut styles for the softer-corner alternative.
What to inspect on a wholesale parcel
When a parcel of princess moissanites lands, look at the four corners of each stone under 10x magnification. You are checking for: (1) existing nicks on the corner points, (2) a thick girdle that hides a chip, (3) asymmetry where one corner is visibly shorter than the others. Any stone with a corner nick should be rejected before it is set, because the chip will only grow.
Beyond the corners, the rest of the princess cut behaves like any other moissanite: it resists scratching at Mohs 9.25, it does not cloud over time, and it cleans easily with warm soapy water. The durability story to tell retail customers is that the stone itself will last for decades, but the setting is the part that needs attention on a princess cut. We recommend advising customers to remove the ring before gym work, heavy lifting, or gardening, even with a protected bezel.
Beyond the corners, the rest of the princess cut behaves like any other moissanite: it resists scratching at Mohs 9.25, it does not cloud over time, and it cleans easily with warm soapy water. The durability story to tell retail customers is that the stone itself will last for decades, but the setting is the part that needs attention on a princess cut. We recommend advising customers to remove the ring before gym work, heavy lifting, or gardening, even with a protected bezel.
Beyond the corners, the rest of the princess cut behaves like any other moissanite: it resists scratching at Mohs 9.25, it does not cloud over time, and it cleans easily with warm soapy water. The durability story to tell retail customers is that the stone itself will last for decades, but the setting is the part that needs attention on a princess cut. We recommend advising customers to remove the ring before gym work, heavy lifting, or gardening, even with a protected bezel.
Beyond the corners, the rest of the princess cut behaves like any other moissanite: it resists scratching at Mohs 9.25, it does not cloud over time, and it cleans easily with warm soapy water. The durability story to tell retail customers is that the stone itself will last for decades, but the setting is the part that needs attention on a princess cut. We recommend advising customers to remove the ring before gym work, heavy lifting, or gardening, even with a protected bezel.
Is princess cut moissanite safe for a right-hand everyday ring?
Yes, if the setting protects the four corners. A bezel or V-prong setting handles daily wear; a thin four-prong solitaire does not.
How does moissanite hardness compare to diamond for princess cuts?
Diamond is 10 on Mohs, moissanite 9.25. In practice both handle everyday wear; the difference shows up in scratch resistance after years, not in the first year.
Can a chipped princess moissanite be repolished?
Yes. A corner chip can usually be polished out by removing 0.1–0.2 mm, but the stone will lose a small amount of weight and may need re-certification.
Do GRA certificates flag corner chips?
GRA certificates grade color, clarity, cut, and carat. They do not specifically call out corner condition. Inspect on the bench; see what GRA covers.
Order from HOLYCOME. We stock princess-cut moissanite in 4x4 to 8x8 mm, D-F VVS, with corners inspected under 10x before shipment. Apply for a wholesale account and request the current princess price list — minimum order 20 stones, mixed sizes allowed.
