Questions about gold marks on service pins: "10/10" or "SOLID GOLD" or "GOLD X" or "X GOLD X"

[HistoryTeacher]

I've been collecting a little tin of marked pins with marks I can't figure out. Mostly I have gotten these at garage sales or estate sales. My Googling around always takes me to the same kind of information like, "What does 14K mean?" I can read standard gold marks, but my acid testing skills are very poor and I don't know what these marks mean. I am hoping someone on here has seen these marks before and can give a clue what I have.

Here are the fronts:

Now the backs (sorry I went from right to left in listing these).
1st Pin: This Goodyear 25 year pin from LGB (Balfour) is marked with what appears to be an "X" is that for "10"? These are usually 10k gold. Not filled.

2nd pin: IBM Quarter Century. These usually come marked 1/10 10GF. I have seen a couple in 14K. What does 10/10 mean?

3rd Pin:
Rutgers Short Course 16; Dieges and Clust. Marked "X Gold X". What does that mean?

4th pin:
ADAA Education Efficiency Loyalty Service
Marked 10K TOP with and S with and arrow through it.

5th Pin:
ADJS with owl pin 29. Back of ADJS marked Moeller Solid Gold.

6th pin: Unknown. This is tiny and has no back marks, but I was wondering if anyone recognized the design.

7th pin; a bar pin marked "Gold Top". Does that mean plate or gold filled? or what?

Any help appreciated!

 

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[pepperj]

This might help answer some of your questions.

Your Guide to Gold Markings and Stamps on Jewelry

Ever see those tiny markings and stamps on gold jewelry? Use this guide to understand what hallmarks are—and what they mean.

www.jewelersmutual.com

 

[luke_00]

Acid testing is the key, and a little practice will give you confidence.
I will say that the 10/10 mark on the IBM pin translates to 1/10-10k Gold Filled. It's not a common mark, but occasionally you'll see 14/10 on a piece, which is 1/10-14k GF.

 

[niffler]

I wonder if "gold top" means that the front is gold but the actual pin part is not...on both the #4 and #7 pictures the pin part looks like base metal.

 

[HistoryTeacher]

Acid testing is the key, and a little practice will give you confidence.
I will say that the 10/10 mark on the IBM pin translates to 1/10-10k Gold Filled. It's not a common mark, but occasionally you'll see 14/10 on a piece, which is 1/10-14k GF.

Thank makes sense. Thanks for the info. I do okay with 14k acids and up, but everything I test seems to test as 10K.

I wonder if "gold top" means that the front is gold but the actual pin part is not...on both the #4 and #7 pictures the pin part looks like base metal.

The pin part does seem to be base metal.