Our five stones

Toughness is the Mohs scale: how well a stone resists scratches. Prices are the lowest 1-carat price in the shop today, in 925 silver, and update with the catalog.

Moissanite is silicon carbide, a crystal that is nearly as hard as diamond (9.25 against 10) and bends light more, so it throws bigger rainbow flashes. It is lab-made; natural moissanite is too rare to cut.

• Does it look like a diamond? In daylight, yes to almost everyone. The tell is the color of the sparkle: more rainbow, less white. Some people prefer it; some find it too flashy above 2 carats.
• Does it pass a diamond tester? The common pen testers read heat, and moissanite conducts heat like diamond, so most of them say "diamond". A jeweler with an electrical tester can tell the difference in seconds.
• Does it get cloudy? No. Early coated stones did; modern moissanite is the same all the way through and cleans with soap and water.
• Color: ours is colorless. Where the maker states a grade, the product page lists it.

A lab-grown diamond is a diamond: pure carbon in the same crystal, with the same hardness, the same sparkle and the same grades. It is grown in a chamber over a few weeks instead of mined. Nobody can tell it from a mined stone by eye or with a normal tester; a lab can, from tiny growth marks.

• Reading the spec table: color runs D (colorless) to K (faint warmth). Clarity runs from FL (flawless) to I (visible marks); anything VS or better shows nothing without a loupe. Each product lists the grades the maker states.
• Why it costs more than moissanite: it takes longer to grow and the rough is harder to cut. At 1 carat it is usually a few times the moissanite price here; the table above shows today's numbers.
• Why it costs less than mined: no mine, no middlemen, and the supply grows every year. That also means it does not hold resale value; neither does a mined diamond once it has been worn.

Sapphire is corundum, aluminum oxide, hardness 9, and the deep blue most people picture. It is the best colored stone for a ring you never take off: it does not chip on a door frame and it cleans like a diamond.

Ruby is the same mineral as sapphire with chromium in it, which makes it red. Same hardness, same care. Pick it when you want color that reads from across a room; it looks warmest in yellow or rose gold.

Emerald is beryl, hardness 7.5 to 8, and almost every emerald, mined or grown, has small internal marks called inclusions. Its green is unlike anything else, which is why people accept the trade: it is the one stone here that can chip if it takes a hard knock on a corner.

• Choose it if you love the color, you take rings off for the gym and housework, and you like a bezel or halo setting that guards the edges.
• Skip it if you want a ring you never think about. Sapphire in green is not something we carry; a moissanite or lab diamond in yellow gold gives a warm look with no care.
• Care: warm water and a soft brush only. Never an ultrasonic cleaner, never hot water, no bleach. See the care guide.

Sapphire, emerald and ruby are sold both lab-grown and mined. The crystal is the same; a lab-grown stone usually shows cleaner color and fewer inclusions for the money, and a mined stone of the same look costs many times more. Each product names its stone. If the origin of a colored stone matters to you, ask before you order and we will tell you what the maker states.