Is anodised zirconium or black zirconium harder wearing?

Neither. Both sit at Mohs 8.5, so they will wear at much the same rate.

They are the same, at 6.5 g/cm³.

Neither. Both are replaced free for life rather than resized, because neither metal can be worked once it is finished.

Black zirconium, starting at £245 against £195. That is about 26% more before any stone or inlay.

Neither, and neither needs to be. The Hallmarking Act covers gold, silver, platinum and palladium only.

Comparison

Anodised zirconium or Black zirconium?

Both are hard enough that daily wear will not show, so the decision comes down to weight, colour and what you want to spend.

The two weigh the same, so neither will feel different on the hand.

Both share the same surface hardness, so they will age at the same rate.

Choose anodised zirconium if anyone who wants colour that will not wear off, or if hands that react to nickel.

Choose black zirconium if anyone who has had a plated black ring wear through, or if manual work.

Still torn? The metal chooser asks six questions and picks one, and it will tell you if neither of these is right.

In both materials

A band of real colour, set between natural metal edges.

Colour on the edges instead of down the middle.

Cut into facets, then coloured, so each plane catches differently.

Is anodised zirconium or black zirconium harder wearing?: Neither. Both sit at Mohs 8.5, so they will wear at much the same rate.
Which is heavier?: They are the same, at 6.5 g/cm³.
Can both be resized?: Neither. Both are replaced free for life rather than resized, because neither metal can be worked once it is finished.
Which costs more?: Black zirconium, starting at £245 against £195. That is about 26% more before any stone or inlay.
Are both hallmarked?: Neither, and neither needs to be. The Hallmarking Act covers gold, silver, platinum and palladium only.