3ctw 9mm Round Moissanite Double Halo Ring, 925 Silver

A double halo is a centre stone surrounded by two rings of smaller ones. The point of the design is scale. The rings lift the apparent size of the centre, so a 9mm round reads closer to the size of a much bigger stone. The halos also protect the edge of the centre stone, which is the part that gets chipped on a solitaire. The total weight is 3ctw across all the stones, with a 9mm round centre, set in 925 sterling silver.

The listing says the ring passes a diamond test, and that needs a careful reading. Moissanite does read as diamond on a basic thermal tester, because it conducts heat in a similar way. An electrical tester or a loupe tells the two apart. So we describe it as what it is, moissanite, which has a refractive index near 2.65 and a hardness of 9.25 on the Mohs scale, close to diamond's 10. For a ring that sees daily wear, that hardness is the real strength.

Sizes run from 4 upward in half steps, so measure a finger at the end of the day, when it is at its largest. The listing gives one style, labelled Style 1, and the other choice is the gift box. It comes with a light box, a black box, a blue box or a white box, so pick the one that suits the moment, particularly if this ring is going to be given as a proposal or a wedding present.

• Stone: round moissanite centre, 9mm, with halo accents
• Total weight: 3ctw
• Setting: double halo
• Metal: 925 sterling silver
• Ring sizes: 4 upward in half steps
• Packaging: light, black, blue or white box