Spotting on 20 dollar gold.

I love the coin ! but there are those that like toning and those that don't. Thanks for the compliment Lehigh96. When I started teaching at my college, there were only 4 in the whole science department. The first year, I taught College chemistry, Photography, and Biology. that was 1967. When I retired in Jan 2004, I was teaching Microbiology and Anatomy/Physiology. I can honestly say I was never bored except in meetings, never the classroom.

Jim

 

Log in or Sign up to hide this ad.

Thanks spock, aka you being the resident gold expert who will hopefully perfer copper like me!....LOL

 

lol i am running around with all the copper you sent over it turns out it was worth its weight in gold

 

The other 10% is copper. Why ? Gold is too soft to endure the rigors of circulation and needs a harder metal to produce a harder final product.

US Gold coins have been 90% gold and 10% copper for a very long time... 1837 to be exact. This was late in the Classic Head design and immediately preceding the Coronet type $2.5s, $5s, and $10s. The only exceptions were the experimental Stellas in 1879 / 1880 ($4 "goloid", a mixture of several metals).

Before that, the earliest US gold coins were 0.9167 gold and 0.0833 gold and silver from 1795 until the Classic head designs in 1834, which were 0.8992 gold and 0.1008 gold and silver (until 1837, at which point they, too, were .900 fine).

Not to be confused with Bullion coins, which are .999 fine. Since they aren't intended for circulation, they don't need copper to harden 'em up.

Prior posts are right - the gold doesn't tone, but copper can.

Those copper spots are due to poor mixing of the alloy.

Copper spot gold coins are not "problem" coins in the since that they bodybag. They have less eye appeal and often sell for discounts.

 

i would like to see this sell for a discount

 

read any metallurgy book GD 100% gold does not tone. (coins are not 100% gold)

 

GD,

I have a degree in metallurgy and I am going to have to agree with Spock on this one. Pure gold will not form an oxide layer under normal atmospheric conditions.

 

Well at least I have an idea for a thesis if I ever get fired from my job and decide to pursue a PHD in metallurgy.

 

you said it yourself its not pure so it tones and 13th 14th century science was not so advanced that they could amke 100% pure gold coins they cant even do that now

 

Good point Spock. Unfortunately, I will need some of your gold coins for my thesis research to determine what level of impurities cause gold to tone, so please send them to me.

 

I dont have any coins on me and GD likes to advance his thesis by buying coins and then experimenting on them so i am sure he will oblige he was planning to go buy a morgan to brush/wipe he might get you some gold too and even conduct the experiment for you

 

my side of the theory has also been proven GD first of all they were 10% not 1 % in the olden days secondly ask any metallurgist they are the experts on metals and metal thoery while 1% impurity might not mean much to a collector it is big in scientific terms. this is a scientific fact not anyone's opinion.

As you said believe what ya want

 

GD if you have a coin that has one millionth impurity it will tone and thats what you will see in the dip. it may be very hard for you to believe that the same way it is very hard for someone to believe (non collector) that a one point grade jump can change the value of a coin by a few thousand dollars but it is true.

what you need to be careful though is separate the toning from the dust or other things flying in the air that get on the coin as that is totally different from the metal toning itself

 

i am talking about the metal gold GD not a gold coin from some time or country at least not yet