Stumped on this one

Swinglow · Oct 27, 2018

On Tuesday I went out for an evening low tide and before the storms chased me out, I pulled a ring that I was sure was gold. It came out of the scoop looking like old dirty low k gold. I hit it with electrolysis and it cleaned up nice. That’s when it got weird. It scratches on a stone like gold, looks like gold, yet 10k acid immediately ate it up. I thought maybe super thick plated gold so I broke the ring with a pair of pliers and scratched it on the break point. Same results. Its stamped “ROBINHOOD” on the inside.

Booooooo!!!

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GroundSweeper · Oct 28, 2018

That’s a toughie, looks like gold from here :?:

dewcon · Oct 28, 2018

Could be plated over brass or a lower k gold. Brass looks awfully close in color to gold. When in doubt ... have it tested. Sure looks good thou.

Walknstik · Oct 28, 2018

In Denmark and Greece 8 karat gold is the minimum legal standard...just a thought?

Skippy SH13 · Oct 28, 2018

Sure looks like gold. to do a rough "test," wipe some foundation on your arm. Yes... FOUNDATION. As in 'makeup'.

Rub the ring across the foundation a bunch... if it leaves a black line, it's likely gold enough to be gold. Brass won't leave a black mark.

The foundation particles are small enough that precious metals (gold and silver) are soft enough that it creates micro-abrasions and rubs tiny bits off that show up as a black streak. it's not a chemical reaction, but rather a physical properties test.

Do this with a known piece, btw. It will also work on old aluminum too, but that's not what you're testing here.

I'm of the opinion that it's probably just low carat gold. I had a 9k gold ring that got eaten by 10K acid. Since 9K can be up to a half-carat, either way, and I knew it was 9K... I sent it to the refinery, it was about 8.7 carat. That explains why it got eaten by 10K acid.

I think you found a winner.

FelixtheCat · Oct 29, 2018

You can also do a specific gravity test in water.

dirtydog · Oct 29, 2018

Did you try 8K acid? I've had a couple not marked and after a file to remove any plating. Both turned out to be 10k.

Swinglow · Oct 29, 2018

dirtydog said:
Did you try 8K acid? I've had a couple not marked and after a file to remove any plating. Both turned out to be 10k.

My testing kit doesn’t have acids below 10k. I need to buy new stuff so I’ll get one that tests lower K. I should just stop being cheap and buy a Kee gold tester

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KinTN · Oct 29, 2018

FelixtheCat said:
You can also do a specific gravity test in water.

Theres your answer. Until you determine SG, youre guessing.

.

Stumped on this one

Swinglow

Elite Member

GroundSweeper

dewcon

Quality Control Expert

Walknstik

Senior Member

Skippy SH13

FelixtheCat

A Moderating Knight of the Round Coil

dirtydog

Swinglow

Elite Member

KinTN

Elite Member

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