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The Karat Question


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I thought this may help someone who is getting different VDI numbers on various pieces of jewelry.

Gold as it comes out of the ground is a pure element that is yellow and relatively soft. That’s your “24 karat gold.” Many people like the yellow color of 24 karat gold, but the lack of hardness can be a disadvantage in jewelery, so it is alloyed with other metals. This affects the color in addition to the hardness. To make white gold, an alloy of palladium and nickel is added to the gold. Jewelers talk about other colors, too: add a little copper for a “pinkish” caste; if you want a “green” tint, add silver. Zinc is added to make the gold harder.

The “karat” tells how much alloy of other metals is used — 18k gold is 75% gold and 25% alloy, 14 karat has more alloy, etc. One might think that yellow gold would always be more expensive than white because it is “purer,” but that isn’t necessarily true. White gold can be more expensive because it’s harder to fabricate. A good gold “manufacturer” is judged by his or her ability to use the different alloys to achieve the qualities desired in jewelry. The head of a ring that holds a gemstone, for example, must be hard but also flexible, so the alloy is important there.

24k gold is 99.99% gold, 22k is 91.67% gold, and 20k is 83.33% gold. Those of such high karatage are most often used in Asia and the Middle East. Generally, 20k or higher is yellow in color. 18k is 75% gold and is the most common karatage in Europe. It’s also popular in America and can be yellow or other colors. 18k white gold made with nickel is very hard. 18k yellow gold is softer than its 14k counterpart. 14k gold is most common in the USA and can be yellow or other colors. 14k white gold is harder and used in prong settings. 14k white gold has a yellowish tinge and is often plated with rhodium (a platinum group metal) to give it a white appearance. 12k gold is 50% gold and is commonly used in class rings and can be other color. 10k gold is 41.67% gold and is common in promotional goods. It’s the lowest alloy that can be called gold in the US and it’s very brittle.

Most of this information came from Donald Fogg, of F.D. Fogg Jewelry in Albuquerque, New Mexico.

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That is a great bit of information and much appreciated...Vdi is unreliable in lots of cases. Found a nice Silver women's necklace a few weeks  back that rang up as a low conductor.... like a gold chain would have...but it was silver.

A METAL DETECTOR IS NOT A GOLD TESTER  

strick 

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That’s interesting.  Possibly a clasp or jump ring of a higher Karat attached to the necklace. Still, a worthy dig from the vdi numbers. Best of luck!

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Pure metals read higher than alloys. So a pure gold item will have a higher target id number than the same size item alloyed with copper or silver, etc.

Large items have higher target id numbers than smaller items made of the same metal. A $1 gold coin reads lower than a $5 gold coin which reads lower than a $20 gold coin.

A silver dime reads lower than a silver dollar.

Therefore small silver items like silver chains or hammered silver coins can have lower target id numbers than larger/thicker gold items.

U.S. jewelers use the karat (k) where 100% pure gold is 24k. Think of the purity as how many “parts” out of 24 are gold versus other metals. 18 parts gold to other metals is 18k. 12 out of 24 parts gold is 12k. 9 out of 24 parts gold in 9k

Miners and gold refiners plus many European jewelers go by “fineness” which is just the percentage of gold multiplied by 10. Absolutely pure gold in considered impossible so most bullion is marked 999.99 fine.

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From http://www.detectorprospector.com/forum/topic/3523-target-id-vdi-numbers-for-gold-nuggets-and-gold-jewelry/gold-nugget-vdi-numbers-herschbach-dfx.jpg

 

 

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Anyone have any good phone apps? Like jewelry makers mark or coin identification Etc. It would be nice to have a good searchable data base on my phone.

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This is the app I use.. https://itunes.apple.com/us/app/coinflation-gold-silver/id535653219?mt=8 

Here is there website.... http://www.coinflation.com

The phone app has melt values for junk gold and silver.

 

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6 hours ago, johnedoe said:

This is the app I use.. https://itunes.apple.com/us/app/coinflation-gold-silver/id535653219?mt=8 

Here is there website.... http://www.coinflation.com

The phone app has melt values for junk gold and silver.

 

Fun scrap calculator app! I like it, Thanks.

 

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