2010 Proof 2c Coin

Quite often the mirrors of proof coins are not quite flat, and certain photographical techiniques make this quite obvious. That being said I'll check out my partners 2010 heritage set and see if her 2c shows the same features.

I have quite a lot of experience at car detailing.
I am also a gem facetor, where I use 50,000 or 100,000 grade diamond paste to achieve polished facets in cut stone.

With more modern cars, it is often found that the paint surface has an 'orange peel' effect, that is the result of a thick clear coat layer over the metallic paint colour layer. This thick layer allows for buffing during ownership over the years to restore a shiny surface and to remove fine 'spider web' scratches, most often seen with black cars in sunny conditions.

The analogy with proof coins is obvious to me. When a die surface field is prepared, it is polished with what appears to me to be about 25,000 grade diamond dust. However, the surface has undulations in it, much like the 'orange peel' effect that occurs in the clear coat surface of new cars.

This lumpy type of surface has a much larger scale of relief, 'topography', if you like, than the diamond dust, and so a shiny, but lumpy surface in the field of the polished die remains.

You may be prompted to ask "why not remove the lumpy surface of the die with coarser diamond dust, before final polishing?" If you did that, some of the coarser diamond dust can get under the masking of the detail, especially near the edges of the detail, thus damaging same.

I certainly use coarser diamond paste for pre polish of gem facets, (3,000 grade), but I don't have a masking problem to contend with.

erkle: Best to send the quartz to a gem facetor. Ask nicely and he is likely to do it for nothing. To polish a facet onto a gem, you need a faceting machine Unfortunately mine is out of action just now because I have to store some other equipment in the area where I work with my faceting machine.

You need the flat surface of the polishing lap top in association with diamond dust, to produce a polished facet.

I use diamond dust of various grades because I work with rough sapphire, which is the second hardest natural stone. Quartz, because it is two orders of Mohs scale softer, can be cut and polished with metal oxide compounds.

Can't use a flat lap on the fields of a planchet (because of the rims), but you can on the die. I don't know if the Mint uses a lap to polish the fields of a die, but if the fields of a coin are slightly lumpy, I suspect not.

Metal oxide polishing and cutting compounds are best obtained from a lapidary store, but in the quantities that I think you may require, they may not be all that economical. Tin or cerium oxides are often used.

I have used cerium oxide for removing fine wiper scratches from the windscreen of my car, but it is a very slow process with hand rubbing. NEVER use an electric buff for this process. You will most certainly WILL crack the windscreen with local overheating. Gauranteed! The professionals use a specialised water cooled buff for this process.

Hand rubbing of the quartz with metal oxide pastes on a perspex (lucite) surface may work, but there is a risk that the polishing compounds can 'pill', then roll betweeen the surface of the lap and the stone, which can cause fine scratching. It is imperative to keep the paste at a fairly watery consistency.