Hi All Im a noobie when it comes to all this stuff, and before i stepped into the deep end and started buying gold and silver, i was just wondering what are good fast ways to determine if a gold/silver bar is stated at what it is. Thinking about it, obviously i could weigh it ( carry around small accurate scales if doing f2f trades?) and that would tell me how many 'oz' or 'grams' it was. Are there any other ways? I guess i'm weary of buying a 1oz bar and only getting .90 of an oz cause some of it has been 'scrapped' off . Maybe I'm paranoid? :lol: Also is there a formula to use to measure the dimensions of a bar and compare it to its weight? cheers!
Buying from a trusted source helps, as does buying certain coins. Depending on your location, there's also a couple of places that have offered to forum members the use of their XRF (X-ray fluorescence) equipment that can test the metal content of pretty much anything - for example, identifying if a sovereign is a genuine 22k sov, or whether it's a 14k jewelers copy. Many members do buy scales - this is super handy for testing coins - for example on the weekend I was shown some fake silver rounds, that were an obvious giveaway due to their weight. For the needs of the average stacker, the cheap digital scales off eBay are great for coins (get the 300-500g 0.01g accuracy ones). You would need larger scales for kilo bars. Easiest thing to do as a new stacker is stick to the "known" stuff like Perth Mint coins and bars (both gold & silver), and 1966 50c coins. Read, read, read - and read some more. There's plenty of fake stuff out there like 100 Mills, German Silver, HGE, Layered, etc that are all just marketing terms for fake alloys or plated copper.
If your looking at buying bars i would stick to Perth mint or PAMP imo they are the best quality out there and internationally recognized.
Buy from well known products from reputable sources until you are comfortable. +1 to the Fisch scale as well although it doesn't cover Perth Mint products. Note to Perth Mint - when you have a bullion product FFS don't f**k around with it's dimensions.
Fisch Wallet #5 - Gold American Buffalo (1oz) Vienna Philharmonic - Austria (1oz) Australian Nugget/Kangaroo (1oz)* *also Lunar 1996-2007 (3 Detectors) http://www.fisch.co.za/orderonline.htm
Since you are in the Gold forum I'm assuming you are talking about small bars (1ozt or less) Calculations from measurements are very dodgy unless all surfaces are dead flat, corners are sharp rightangles etc. A far more accurate way is to work out the SG (Density) from a couple of weighings, I have no gold bars so will demonstrate a simple method using a 1 ozt silver coin. - NOTE: I had scales last week that measured to 2 decimal places - Cost $7 - Neighbor offered me $20 for them *Sold* Have 2 new ones ordered. - But at the moment only scales I have only gp to 1 Decimal place. So this will not be accurate but shows the method. First - Weigh the Dry coin or bar. Photo shows 31.6g (Actual weight is higher.) Next ,get a dixie Cup with enough water in it so you can immerse the coin or bar without it touching the side or bottom of the cup, Place cup and water on scale the press TARE to zero the scales. Make up a sling to hold the coin or bar with silk threads or fine waxed cotton, and lower it into the water without touching the cup. In photo Im cheating and using a pair of tweezers (not good - tweezer ends in water adding extra volume.) You are not lowering weight into water - you are lowering VOLUME - You are holding the weight. Read the weight showing on scales when coin or bar is fully submerged. This is the weight of the displaced water. Photo shows 3.0g (from previous weighings on other scales this is normally 3.01 or 3,02 on a 1 ounce silver coin...) So to find the SG (Density) divide the dry weight by the second weight 31.6 / 3.0 = 10.53 (SG of silver is 10.5) with 2 decimal place scales you will get greater accuracy This method with good scales will give very accurate results, if the coin was a silver plated copper coin it would have shown a SC of about 8.9 and will work on any size weight or material - Below are some SG's for various metals Silver, 10.5. Platinum, 21.4. Palladium, 12.0. Copper, 9.0. 9ct, 10.9 to 12.7. - Depends on alloy mix 14ct, 12.9 to 14.6. - Depends on alloy mix 18ct Yellow, 15.2 to 15.9 . - Depends on alloy mix 24ct Gold, 19.3. . This method will sort out most fakes, but if in doubt use other testing methods available
i'm using the one at my work, (Chem teacher) you just reminded me i'll get kids to clean some of my coins (child labour does work well)
used the test today witht he kids in my chem class with another 5 mark coin to compare the original one is 900/1000 and specific gravity (SG) cam to be around 10.1(used tweezers too). THe fake coin its pictured in the thread "querry" had a SG of 7.8. Nice test ty
Yep - Its a dead easy test to do and its quite accurate, sometimes the simple way is the best way. I thought there must be a few people in here that have known fake coins and was hoping someone would test using this method and report result, I'm curious to know just how close can they get the fakes to the real ones
see if gold was cheap theyd be able to do it easy cause copper is 9 and pure gold is 19.3 so just make an alloy of mostly copper probably like 3-4 ct gold. In the scenario that someone was predicting forgot who but i read it here on SS where silver would surpass or equate gold's value that would be viable option , and ud probably have to use other metals too since copper would be give u too much red of a colour. So ud have to balance the colour, SG and quality of ure craftmanship to make a good fake coin oh and the alloy u make would need to be fairly anti corrosive as silver is.
Another way is to use vernier callipers to measure the diameter and a micrometer to measure the thickness. Volume = area x thickness. Density is mass ( i.e. weight ) / volume. Try to measure near the centre and avoid the rim which can be raised. Most fakes are easily spotted as underweight and slightly thicker. Reduced weight on UNC looking coins is worth investigating. If the diameter is correct ( most fakes are ) and the weight seems low then sometimes this can be wear so should be thinner. Fakes however will be thicker.
you will never get good results trying to work out volume of a coin from measurements use vernier callipers to measure the diameter Problem 1 - the coin is fluted ( reeded, milled call it what you want.) you are measuring the max diameter (top of flutes). on a fluted coin there are 3 Diameters, Diameter MAX (top of fluting) Diameter MIN (at base of fluting) And Diameter MEAN or AVERAGE. Diameter MEAN is the measurement you need for calculating volume, its about halfway between the top of fluting and bottom of fluting. To visualize this, get a tin of filler (Spackle) and fill in all the valleys around coin till it is smooth and flat right around the coin, now convert this amount of filler into Gold. That's quite a big margin of error. a micrometer to measure the thickness near the centre Same deal here, you are measuring the High points of the relief, Again get some filler and trowel it into all the low points of the coin, trowel it smooth and flat, do it to both sides of the coin, That's a lot of filler, convert that into Gold. You big margin of error is now a Massive margin of error I think I understated things when I said trying to work out volume from measurements is 'Dodgy', it makes about as much sense as pissing into the wind. The only reliable way to get the volume of a coin is by the displacement method. The weight shown in the second reading that I showed is the Volume - remember 1 cubic centimeter of water weighs 1g, so Volume of coin is the same as the weight of the displaced water..
What is a fisch worth and where does one obtain one? Sorry for the laziness in tracking one down but I am sure it would be quicker to enquire here and I more reliable. Thanks in advance.
Thought they'd just been found to be in violation of the patent and were shut down? Their site was down a few weeks ago - now it's back.
I am looking at the i-c-g as well. Questions: What is 2 rand? and would you personally perfer to pay a bit more for Fisch or just get a scale off ebay? We are starting with a set of five scales useful in validating the following bullion coins, the most frequently counterfeited around the world: Krugerrand, American Double Eagle, Isle of Man, Angel Britannia (1, 1/2, 1/4, and 1/10 oz), British Sovereign, and 2 Rand
