US 6,143,572 A · Method for detecting imitation gold, using a pen-like device

Abstract

A pen-like device having a scriber for scratching a deep groove in a yellow colored, metal article object, such as jewelry, being tested for the gold content thereof, and an applicator provided on an opposite end of the pen-like device for conveying an acid solution, which is housed within the pen-like device, onto, around and in the groove to observe whether there is a color change to the testing area, on which the acid solution was applied, making the the testing area darker or black, where such a color change would indicate that the metal article or object is imitation gold, or has a gold content which is less than minimum karat requirement of the test. The acid solution includes a specific percentage of nitric acid which changes the color of the testing area when in contact with most imitation gold materials, preferably a specific percentage of hydrochloric acid to coact with the nitric acid, and a specific percentage of selenious acid which changes the color of the testing area when contacting a bronze or brass material. The specific percentage of each acid can easily be determined, for testing gold having a specific karat value.

Claims8

Dependent claims

A hand-held device for use in detecting imitation gold, comprising:

a hollow body including scriber means for scratching a groove in a test area surface of a metal article which is being tested for its gold content as compared to a minimum karat requirement;
said hollow body also including applicator means for applying a specific acid solution on the test area surface to observe any color change to the test area surface and to the groove therein;
said specific acid solution being housed within said hollow body in communication with said applicator means;
said specific acid solution including first acid means for changing color of bronze and brass when in contact therewith;
said first acid means being selenious acid;
and
said specific acid solution also including second acid means for changing color of imitation gold metal articles, other than bronze and brass, when in contact therewith;
said second acid means being a mixture of nitric acid and hydrochloric acid;
whereby a color change to any part of the test area surface, including the groove, making the part darker, indicates that the metal article being tested is imitation gold, or that its gold content is less than the minimum karat requirement of the test.

6 more elements

Dependencies are inferred from the claim text.

Method for detecting imitation gold, using a pen-like device

Life of this patent

Method for detecting imitation gold, using a pen-like device

Life of this patent

Abstract

Claims8