18ct gold or Black zirconium?

Which is heavier, 18ct gold or black zirconium?

18ct gold is heavier, about 2.4 times the weight of black zirconium for the same ring. A 6mm band in size N comes to about 7.6g in 18ct gold and 3.2g in black zirconium.

Worked out from the reference densities (15.7 and 6.5 g/cm³) with the same model as our ring weight calculator, where you can set your own size, width and thickness. A bigger size adds a little more metal: the size N page and the other size pages give the weights at each size.

Is 18ct gold more expensive than black zirconium?

Black zirconium costs less: 18ct gold rings start at £689 and black zirconium rings at £199 in our range. 18ct gold carries the cost of the precious metal itself, which is why it starts higher; black zirconium is priced on the making, not on bullion.

Every ring is made to order in your size, and engraving is free on every ring whose page offers it.

Which is harder wearing?

Black zirconium has the harder surface: Mohs 8 against 3 for 18ct gold, so it picks up fewer everyday marks. 18ct gold marks sooner, and any jeweller can polish it back.

18ct gold. 18ct is 75% gold, which gives it the deepest colour and real weight on the finger. It is a little softer than 9ct, so it shows marks a little sooner, and they polish out at any jeweller. Yellow and rose gold need nothing more; white gold is often rhodium plated, and replating brings back its bright white whenever you want it.

Black zirconium. The black is a hard ceramic oxide grown into the surface by heat, around Mohs 8, far harder than gold, so everyday knocks that mark a gold band leave it looking the same. It is scratch resistant rather than scratch proof: a hard blow against stone or steel can mark it, and a pale line is often metal rubbed off something else, which cleans away. Take it off for gardening, climbing and the gym, and if it is ever marked, our maker refinishes black zirconium depending on the damage.

Want gold that wears harder? 9ct gold is the harder alloy and costs less than 18ct. Compare 9ct gold and black zirconium

Can 18ct gold and black zirconium rings be resized?

18ct gold: Yes. A plain 18ct gold band can be made larger or smaller by a jeweller, the way wedding rings have always been resized. The exception is a band set with stones all the way round, where there is nowhere to cut without disturbing a stone, so on those the size is settled when you order.

Black zirconium: Not in the usual way. The black is grown into the surface of the metal, so cutting or machining the band would show bright metal underneath. That is why the size is settled before the ring is made, and every ring is made to that measurement.

Either way, getting the size right first is the easy part: the free ring size finder measures it at home in a couple of minutes, and the resizing guide explains the differences between metals.

Sensitive skin and hallmarks

18ct gold is a gold alloy, and white gold can be alloyed with nickel, so if you know you react to nickel, a hypoallergenic metal such as platinum, titanium or zirconium is the easy choice. Black zirconium is hypoallergenic and a common choice for sensitive skin. The metal allergy guide explains what causes a rash under a ring.

Gold, silver, platinum and palladium are hallmarked by law above the exemption weights. The marks go inside the band, where you can read the fineness for yourself. Titanium and zirconium are not precious metals, so there is no hallmark and none is required. Where a ring carries a solid gold inlay, that gold is hallmarked at Birmingham. The UK hallmarking guide explains each mark.