Cleaning Gold Nuggets
Natural gold nuggets as they are recovered from nature are not likely to sparkle and gleam as a piece of gold jewellery in the shops. A mineral collector may want it just that untreated natural way with maybe just a toothbrush clean to remove any soil.
There are quite legitimate ways in enhancing the beauty of nuggets intended for jewellery, to be worn next to ones skin. A slight polish is all that is needed highlighting the high points of the nugget. The idea is not to overdo it and not over polish the piece.
Nuggets have natural imperfections and colouration, that gives them character. An interesting shape can make it more desirable and with imagination all sort of things can be seen. It may look like a dingo howling or like the map of Australia or a tear drop.
Each gold nugget is unique, only one of a kind.
If a nugget is over polished it could be mistaken for a manufactured fake nugget. A fake is usually very pretty and shiny because the casting process produces that even homogenous look. An experienced person can always tell the difference.
To clean gold you can use:
TOOTH BRUSH Initial clean, out in the bush, Used on gold for a mineral collector.
ACID Used to remove rock, remove surface oxides, brighten surface, expose crystalline formations in quartz specimens. This method employs some very dangerous, corrosive and deadly acids and is not recommended. Used by experts only under lab conditions and strict safety regime.
TUMBLER Used for jewellery pieces
Tumbler Method
What you need:
Tumbler, steel shot, burnishing compound, old electric frying pan, plastic kitchen sieve, nuggets.
How:
Fill
your barrel/bowl with 2kg steel shot, add nuggets, add about 1 tea spoon of
burnishing compound and water, seal barrel and turn on tumbler. Water level
should be just below the shot level. The right mix should be of a slight
creamy consistency.Check periodically the progress of the operation by stopping the tumbler and removing one or two nuggets for inspection. See if the desired result is achieved or if it has to run longer. A little more water if it is too thick
The burnishing compound (acid free detergent specially formulated) is added to give the nugget a shine and make the steel shot roll smoothly. Don't worry it is not wearing your nugget away. The shot just rolls on the surface of the nuggets.
On completion of the tumbling the nuggets and steel shot are emptied together into the sieve over a plastic gold pan and thoroughly rinsed in water. Next this lot is spread over a towel and the nuggets are picked out by hand or tweezers. The still wet shot is then dried in the electric frying pan ready for the next time.
Inspect all nuggets carefully and remove any stuck pellets of shot from the nuggets.
I have used this method for many years and I still have most of my original shot in good condition with no rust. You can also get a shot storage solution that stops your shot from rusting away. Stainless steel shot is also available. As your shot ages it may become pitted and may need replacing. You can rejuvenate the shot by running a load through the tumbler with water and tin oxide to try and give them a polish.
Any rotary tumbler (Lortone) will work but the vibrating type (Gyroc) will do the job quicker. I knew a person that used only nuggets without the shot with excellent results. (I never had that many at once to fill a barrel) Some gold nuggets polish very quickly and others seem to take longer. Some nuggets are harder and take longer to take a shine.