Acid reactions question

[Trekbonita]

Hi i usually use nitric acid and schweter solution to test gold and silver but i got the next question:

After using the schweter solution on some pieces labeled 925 i get no color on the acid and a dark gray mark on the silver. What metal is that? ( silver reaction is usually red to dark brown on other pieces ( on the acid) and white on the silver)

On gold i have tested some pieces with nitric 35% and it just create a soft green reaction on the acid and no mark on the gold no reaction with the schweter. ( so no bronze or brass)

Also what type of silver solder reacts deep black with the schweter solution

 

[Martijn]

Welcome to the forum.
I found this list from this site: it says its schwerters-solution.
I hope that helps.
http://ozcott.com/NomadTronics/product/schwerters-solution/

Martijn.

 

[Trekbonita]

Welcome to the forum.
I found this list from this site: it says its schwerters-solution.
I hope that helps.
http://ozcott.com/NomadTronics/product/schwerters-solution/View attachment 50704

Martijn.

Hi, thanks for your answer. Sadly no acid reaction and dark gray stain isnt in the list, and an alloy of silver and iron isnt likely as silver solder.

 

[eaglekeeper]

How old is the silver testing solution and is the solution still red..... After awhile mine seems to degrade and not work right.

 

[Trekbonita]

Is new