How to make a silver testing kit using Schwerter's solution

When Potassium dichromate is dissolved in an approximately 35% nitric acid the solution created is called Schwerter's solution. Schwerter's solution is used to test for the presence of various metals, notably for determination of silver purity.

Cautions:
Avoid breathing the fumes and avoid skin contact. Nitric Acid, Hydrochloric Acid, and Aqua Regia are extremely poisonous and corrosive !

Since the testing procedure requires the use of dangerous acids, special care should be taken not to spill or allow acid to touch the skin.

If acid comes in contact with the skin, wash the affected area with a mild soap and water as quickly as possible.

NEVER POUR WATER INTO ACID.  YOU MUST POUR ACID INTO WATER!!

You will need:
Nitric Acid (C.P.),
distilled water to mix the test solutions.
Potassium dichromate salts for making Schwerter's testing fluid.

Two acid bottles with ground glass stoppers and applicators
A Test stone
A graduated cylinder is recommended to measure the required proportions.
These items may be obtained from laboratory or chemical supply houses or local drug companies.

Mix 10 grams potassium dichromate salts with the ¾ oz. nitric acid plus ¼ oz. distilled water.
NEVER POUR WATER INTO ACID.  YOU MUST POUR ACID INTO WATER!!

Testing Silver
Scratch the article with a file and apply a drop of Nitric Acid. If it turns green, it is plated. If a cloudy cream, it is sterling or better. (Some silver contains less than 90% fine silver).

Testing Base Metals with Schwerter Salts
File a notch in the test piece and apply a drop of Schwerter's Solution in the notch.
Observe the colour reaction.

Schwerter's solution indications
Brass - Dark Brown
Copper - Brown
Nickel - Blue
Palladium - None
Gold - None
- Silver Pure - Bright Red
- Silver .925 - Dark Red
- Silver .800 - Brown
- Silver .500 - Green
Lead - Yellow
Tin - Yellow

Buy a silver testing kit for £12.95

How to make a simple silver testing kit

Here are two simple methods to quickly test if the metal you are looking at has any silver in it.


Both of these methods will help you determine if the metal you are testing has any silver in it. It won't tell you the amount or purity of the silver content contained.


Method 1:
Use American Mustard:
American Mustard is the one used on hot dogs. It is bright yellow, contains mustard tumeric and vinegar and is mild to the taste.
This type of mustard has a high sulpher content and when applied to silver will cause the metal to tarnish.

1. Use a stone or cloth to expose a little of the silver.
2. Apply a little warmed American mustard to the cleaned silver for a few moments.
3. Wipe off the mustard and if you see a black tarnish mark then you have some silver.
4. The silver can then be cleaned off with a small amount of white vinegar.

Method 2:
Using Two Matches to test for Silver.
The flame from a freshly struck match releases its sulpher content which causes silver to tarnish.
The most sulpher is relased as the match catches fire.

1.Press a match head against the silver.
2.Light a second match and set the first match on fire.
3.Wash burnt fingers under cold tap quickly!
4 If tarnish exists on the object then you have some silver.

Both of these examples will work to show silver but they will only tell you that the tested metal has silver in it.
In this way it will not tell you about the purity of the silver.
To test the purtiy of silver you need differnt chemicals.

See How to test the purity of Silver.

Buy a Silver Testing Kit

If you are unsure about the purity of your silver or even if the metal you are looking at even is Silver, then you probably need a Silver Testing Kit.

A silver testing kit uses a mix of chemicals that react on contact with silver. The contact mark made can be then wiped off after you have identified the metal.

This kit provides an accurate, affordable and easy-to-use means of testing precious metals. The kits are produced in a specialist laboratory (fully compliant with ISO9001:2008 standards) This ensures that the products are always manufactured to the highest industry standards.

The kits are all supplied laboratory-fresh with a long shelf-life.

This is a special solution for testing only silver. Unlike other kits which use the same solution for silver and gold, this kit has been designed for users who have no need to test gold.
See More

Contents:
Silver Testing Solution.
Full testing instructions.
Miniature needle file.
Used to check whether an item is plated, by removing a small part of the surface in a concealed spot before retesting.
Magnet.
Allows the item to be identified as possibly steel if it tests negative for silver.

Just apply a small spot of the test solution to the metal and wait. The spot will change colour depending on the metal underneath. If it turns red you have Silver. You can use the file to test if the metal is plated.

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