Zr refers to the elemental symbol for zirconium.
79 refers to the atomic number for gold.
The black section of this ring is machined from a solid bar of zirconium which starts off a silver colour. A channel is cut into the edge of the ring to allow a band of 18 carat gold to be precisely fitted. The ring is then seamlessly re-finished to blend the gold and zirconium together perfectly.
The finished piece begins a heat treatment process to oxidise the zirconium, building a ceramic oxide passivation layer on the surface, creating the black appearance. This black zirconium layer is highly durable with a hardness similar to sapphire.
Zr-79 is custom made and requires a lead time of 3-4 weeks. The finish and dimensions can be altered to your specifications.