CONNECT all the cords and the gel tube. The GT-3000 from Tri Electronics is the electronic tester we show here, and it works with batteries and a tube of gel. I take it apart when done, so I have to connect the cords back to the tester and take the gel out of the refrigerator. It seems to last longer if refrigerated. Be sure the tip is clean and that there is gel at the tip.
PLACE the item in the clip. There is an alligator clip on the backboard. This may be rough on your jewelry, so try to set the jewelry in carefully and clip softly. Once you have the item in the clip, turn the tester on. Give it a few seconds to register. Touch the tip of the tester to the piece of metal you have in the clip, making sure you do not touch the clip with the testing pen.
While holding the pen to the metal you are testing, push the TEST button and wait three seconds for a reading. You will get a reading from an MINUS to 1100 or so, and there is a graph on the tester itself that indicates the karat for the different numbers.
READ the number and COMPARE to the graph on the tester. This piece shows a reading of 806. Anything between 675 and 865 in yellow gold is 13 to 14k and is considered 14k. We know that this one is gold, although it is UNMARKED. You would be surprised how much unmarked gold is available in jewelry boxes. When I was young many years ago, gold was $35 an OUNCE, so there was more gold jewelry available to the middle class.