Acid Test for Gold

How You Can Find the Number of Karats in Gold

If you wish to find out if a piece of jewelry is made of gold, touch it with a glass stopper which has been wetted with nitric acid. If it is pure gold it will remain untouched and unchanged; if not, the solution will become blue from the formation of nitrate of copper. (False "gold" always contains copper.)

To find the number of karats in a gold object is not as easy as testing for gold content. First, weigh the gold object. Then break it up and mix it with seven times its weight in silver. Beat this mixture into thin leaves and then add nitric acid. The silver and copper will dissolve. Now fuse the remaining gold and weigh it. Compare the first and last weights: the difference will be equal to the number of karats of pure gold. Repeat several times to check.


Related Articles

Fishing Bait - 10 Oil-Based Formulas

Mix together 5 parts oil of rhodium and 2 parts oil of cumin.

Our Multipage Plastics Report

In order to prepare a foam of given density, thoroughly mix Polylite 8601 with the necessary amount of Catalyst R1 and water.

How to Make Lamps and Vases from Bottles

To do this you must place the glass under water completely, then with a pair of ordinary scissors, proceed to cut the glass as you would paper or cloth. This method is, of course, not as smooth as job as the methods described above.

Flexible Mold Compound

This new mold material is much superior to ordinary gelatin (mold glue) and is very easily made. It does not shrink or dry out like ordinary casting gelatins.

Jewelry From "Ordinary" Treasures

Almost everyone has a box of sparkling old buttons from Grandma's sewing chest to marvel at, or set of dominoes, checkers or mah-jongg pieces rescued from a flea market.

"Lenz-Brite" Liquid Eyeglass Cleaner And "Anti-Fog"

This product is a small plastic vial with screw cap, in which a piece of chemically saturated folded felt is packed.

Homemade Kentucky Beer (15 Gallons)

Use 15 gallon plastic garbage can with clip on lid. You need:

Six Simple Plastics Formulas

This is the age of plastics! One of the most amazing developments in this age of wonders . . . NEW developments and discoveries are constantly being made in the plastic field. Here is a truly rich field for experimentation.

How to Cash in with Simple Formulas

You can copy any of these Formulas and sell to other Agents, or put them together in packages - under your own name - and sell to Agents.

Making Your Own Plastic Molded Objects

This plastic is particularly adaptable for making molds and light castings requiring tensile strength but very clear outline. It may also be used for making ornaments and novelties. However, as this is flammable, do not use for ashtrays.