plating, anodizing, & finishing Q&As since 1989
Gold Plating the Magnetite Inclusions in Magnetite Jade Knife Handles
September 26, 2012
Q. I'm planning to do some decorative plating that also needs to be fairly robust. I am taking Magnetite Jade, which is a black jade in which there is magnetite inclusions (Fe3O4), shaping it as handles in knives I make. Once shaped and polished, I want to plate the magnetite with gold. I presume I should use a cobalt gold solution (24 kt), but do I need any pre-plating layers (copper/nickel or just nickel)? Any suggestion on gold thickness to minimize wear? I don't expect these knives will be extensively handled, but need to accommodate some wear resistance. Would I be better off brush plating or immersion plating?Dan Fronefield
- Colorado Springs, Colorado, USA
A. Hi Dan. I think you could bright nickel plate the inclusions before gold plating to give some shine without an unaffordable gold thickness, or polish the magnetite before plating and plate directly. I see this stuff on the stones of rings and earrings, but I think your knife handles will experience a hundred times as much wear. If the plating is a protuberance, it will wear off quickly even if fairly heavy. Does it sound remotely possible to etch the magnetite before plating so it is slightly recessed below the stone? Then the plating would probably last indefinitely.
I see jewelry stores advertising that they gold plate it, and I suspect that it's done in a tank, but I don't know.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 29, 2012
Q. Hmm, I never thought to etch the magnetite down. I can certainly try that although that is likely to leave a rough surface that I cannot subsequently polish.
I think you are right that at minimum there needs to be a nickel plating first. I plan to polish the piece up to 50,000 to 100,000 diamond grit, which will be a super polish on the jade ... not sure how the magnetite will polish.
I'll likely plate the gold to twice the thickness usually used on jewelry. I don't know if this will be "enough".
- Peyton, Colorado, USA
August 7, 2016
A. I have been plating the magnetite for quite a while and I plate directly on the magnetite. The stone is well polished before I start; and after plating I give it a short polish to bring a good shine to the gold. Only used the pieces for pendants so far.Irv Baker
- Novato, California USA