Cleaning Gold and Things 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 fake. 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. Lortone 2 Barrel Tumbler Coin and relic hunters, transform your finds into interesting display pieces. Works well on coins, rings, jewellery, brass artifacts, shells, buttons, locks, knives and spoons etc. Make sure pieces are clean and all surface corrosion has been removed first. Some household cleaners may also help with 'CLR' also popular on modern coins. Cleaning coins of rarity and value is a specialist job. If in doubt seek help before starting to scratch away all potential value. Acid Method The only method I am happy to recommend is the salt and vinegar mix. A mix of salt and vinegar (experiment here, not critical) is placed in a narrow glass or plastic container with your nuggets and shaken back and forth till they burnish naturally against each other. A pleasant shine develops on the nuggets. You do need a few nuggets for this to work.
 Specific Gravity Test HOW MUCH GOLD IS IN THAT LUMP OF QUARTZ? Fair enough question, we know the weight in air, we can determine the weight in water and the rest just follows physics. The specific gravity of gold is known, the specific gravity of quartz is known, chuck it all into a formula and presto, the result is ready. Well not quite, in nature gold is never pure and quartz can have all sorts of other impurities included so the results are never exact. Over many years of tests, personal observations have shown that the actual gold content is generally more. In fact up to 10% more gold than the calculation shows. You will only know for sure after breaking up the specimen and dollying it up and panning it off. You would not do this to a beautiful one of a kind specimen but to get an approximate idea on its value this formula comes pretty close (maybe add that 10%). Specific gravity test for gold
How much gold is in the specimen?
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