making gold testing solution

hi does any one know how to make the gold testing solution for 10kt, 14kt, 18kt, 24KT TESTING SOLUTION .SAY YOU GOT A 14KT GOLD CHAIN SCRACTH IT ON THE GOLD TESTING ROCK, THEN ADD THE SOLUTION .


how would you make that solution and whats in it

Here are the formulas that came with a test kit I once bought. It came with empty glass bottles and gave the formulas to make up the solutions.

10K - 3/4 ounce, by volume, nitric acid - 1/4 ounce distilled water

14K - 4/5 ounce nitric acid - 1/5 ounce dist. water - 10 drops of hydrochloric acid

18K - 1/5 ounce nitric acid - 1/5 ounce dist. water - 3/5 ounce hydrochloric acid

Silver test soln. - Dissolve 20 grams of potassium dichromate in 3/4 ounce of nitric acid mixed with 1/4 ounce of distilled water. A drop of this on a silver alloy will turn red, the higher the silver, the redder the drop. You have to see it

I have seen other different formulas.

This was my question on this post:
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=307
Take a look and you should find infos.

Well, we don't know Nitric Acid concentration with this receipe...

WOULD YOU HAVE THAT MIX BREAKDOWN IN GRAMS

I had problems figuring out what you guys meant. The formulas are in fluid ounces, not weight ounces. There are 29.6 mL in a fluid ounce. I just copied it off the instructions. Please not that I have never mixed these up. I always used the various pre-mixed solutions that I bought from companies that sell jeweler's supplies. I also see them on eBay. They also have 22KT. They're cheap.

If you can measure mL, milliliters, that would be the easiest. Here are the exact numbers. You can probably round them off. Just measure them as accurately as you can. Fluid ozs. don't convert to mL that evenly.

10KT - 22.2 mL nitric - 7.4 mL distilled water
14KT - 23.7 mL nitric - 5.9 mL distilled water - 10 drops hydrochloric
18KT - 5.9 mL nitric - 5.9mL distilled water - 17.8 mL hydrochloric
Silver - 20 grams potassium dichromate - 22.2 mL nitric - 7.4 ml distilled water

you the best thanks

thanks for the info

just one question on the 14k is it 10 drops hcl or 10 ml

Drops. 10 drops is about .5 mL or, a little less. Depends on the eyedropper.

I was wondering, do the Nitric Acid concentration affects anything at all ?
Or maybe I'm a little bit mixed up ??

Noxx,

If I understand your question right, the answer is yes.

When you apply the acid to the streaks on the touchstone, you are looking for the amount of attack, the rate of attack, and the color produced. Stronger or weaker nitric will effect these. It's a visual thing. You compare these unknown streaks, side by side, at the same time, with streaks made with gold of known karats, usually from gold testing needles or from gold objects that you know the karat of. It's really pretty simple, once you get the hang of it. Play with it. Make streaks with different things and try all the acids on them. Be very careful not to cross contaminate the acids.

Where are you in Quebec? I was stationed in the Air Force, for 3 years, near Caribou, Maine, about 40 miles from Quebec. Spent most of my time off in Quebec. Beautiful but cold. Went to the winter carnival in Quebec City one year. Great fun. Beautiful women.

Noxx,
Do you mean the concentration of the nitric that you buy, or start out with
like 70%? Or if a lower concentration will work or be better?

The formulas I gave are based on reagent grade or technical grade nitric acid, although, the technical grade is a little weaker. Since this is a comparison thing - known karat vs unknown - slight variations in nitric strength shouldn't make that much difference. When I use the commercial test acids, there are slight differences in strength. When I buy a fresh one, I have to get used to it's differences. Also, the acids containing hydrochloric will get weaker over time.

The main things are that your 10KT acid doesn't dissolve a 14KT streak or the 14KT acid doesn't dissolve an 18KT streak. I should say dissolve quickly. If you let them sit long enough, there could be some attack. For this reason, I usually cut my observation off at, say, 10 seconds.

Ok now I understand ! Like you say it's a comparison thing. So I absolutly need needles wich are «certified» 10k gold.

I'm about 10 mins from Quebec city. Yes it's cold. But it's beautiful. Did you ever eat freshly made Maple tofty ? Soooo good !

I would like to know if test stones are special stones. Is it possible to use a fine grit sand paper ? ( The one used for metals )
Thanks

tester

What do you mean ? I don't understand...

you were asking about the gold testing rock,if im not mistaken,you scrape the gold on the rock,its not exactly a rock they just call it that,then add the acid

OK then if it not a rock, can I use something else ? Or this rock has something special in it ?
Thanks

it looks like this you can buy it in any jewlery supply