DR. HANNEMAN'S MINERAL COLLECTION WILL BE AVAILABLE FOR SALE IN THE NEAR FUTURE
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 Post subject: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 3:40 am 
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Hi!
I have this small unmarked diamond brooch. I think it's platinum, but I am not sure. Since it's unmarked I can only guess it's age and I am hoping someone may have an answer.
It has a trombone clasp and by style I'm thinking 1940-1950.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 2:01 pm 
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The pin could have been made mid-century BUT the bows in the 50's were typically more stylized and flamboyant.
Image

What is the method of manufacture on the piece? Was it fabricated or cast?
I suspect it was made later. I would call it mid to late 20th century if it were in front of me.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 2:12 pm 
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Always thankful for your reply!
I think it's fabricated, clear tool marks in some places. So, 1950-1990s? If it's platinum, that is. I think I've read some were that platinum was'nt always hallmarked until after 1990 (correct?)


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 2:48 pm 
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In the US, we are completely loosey goosey when it comes to quality stamps or maker's marks.
There is nothing which legally states American jewelry must be stamped with anything. Although, technically, if something is quality stamped, it should be accompanied by a maker's mark for recourse if the item is improperly represented. It is never enforced.

There was an issue in the 80's with overstating gold's purity when everyone was selling gold chains by the gram. The Feds went after these abusers for a short while.

Back to your pin.
When were pins popular?
Brooches have made a bit of a comeback but they were not popular in the 80s through 2000.
The diamonds (relatively large tables) look 60s-70s to me.
80's would have been yellow gold, fashion-wise.

Get a box of metal testing acids. It's a relatively reliable way to determine metal purity.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 4:04 pm 
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I do have a metal testning kit, although I was'nt able to get one that test for platinum. Only gold purity, and it was difficult to get. In Sweden we hobbyists are'nt really allowed to buy these things. Apperantly we can't be trusted with such dangerous chemicals.
Anyway, I tested it and at 18k it sort of flaked greenish. I looked it up and found that it could be platinum. It's also magnetic.
What do you think, platinum?


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 6:26 pm 
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Magnetic? Precious metal is NOT magnetic.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Fri Nov 13, 2020 10:41 pm 
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If magnetic it is not platinum or gold, or silver, that is for sure.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Sat Nov 14, 2020 9:22 am 
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Platinum is paramagnetic and attracts to a magnet when floated. I should have mentiond the floating..


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Sun Nov 15, 2020 12:23 pm 
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Come on.....floating your brooch to test for "paramagnetism" is eccentric at best.
Do you have 22k gold acid? If you the line left on your scratch plate remains, it is likely plat.


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Mon Nov 16, 2020 5:02 am 
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Eccentric? I'll take it :)

I have 21,6 K, 18k and 14 k gold acid.
With 14K the line remains, above 14K the metal sort of floats in the acid after about 1 minute but it doesn't disolve.

This is why I floated the brooch. I wanted to know if it was unmarked white gold or something else. It seemed a bit strange that a fairly modern gold brooch did'nt have any purity marks.

So, not platinum?


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 Post subject: Re: Help dating unmarked brooch
PostPosted: Mon Nov 16, 2020 6:06 pm 
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I don't understand your testing methods.
Why are you floating stuff?

Make a mark on your scratch plate with the pin.
Does your 21.6K acid dissolve the mark?

If the mark dissolves it is not platinum.


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