Gold Testing with a Tri-Electronic Tester

Gold Testing with a Tri-Electronic Tester

Many pieces of antique gold jewellery (particularly from the Georgian era or pieces which are handcrafted) are unmarked and therefore gold testing is necessary. This article is a practical guide to using an electronic gold tester made by TRI electronics (I personally have the GXL-18 model.).  

This is my decimation of the information in the TRI Electronics user manual which I hope makes a good quick reference for those interested.  HOWEVER – PLEASE ALWAYS REFER TO THE MANUFACTURERS INSTRUCTIONS FOR THE FINAL SAY ON HOW TO USE THESE TESTERS. 

 

OPERATION PROCEDURE

The procedure for testing can be shortened to the following easy to remember four words:

LOAD – CONNECT- SELECT- TEST

For more details, see below: 

1) Load the polyethylene gel tube in accordance with the manufacturers instructions.

2) Connect the following:

a) The black wire to the sensor’s plug outlet.

b) The black and red wire connector to the display unit.

c) The red wire to the testing plate.

3) Turn the unit ON. The unit should now read ‘G-XL-18 READY TO TEST…’

4) Selecting a point to test: 

a) Make sure the point to test is close to BUT NEVER TOUCHING the alligator clip.

b) Do not allow the gel to touch the alligator clip as this will corrode it.

c) Thoroughly clean the testing point with the eraser.

5) The First Part of the Test

  1. Place a tissue, paper towel or rag under the tip of the sensor.
  2. Hold the sensor in a vertical position with the nozzle down.
  3. Twist the Rotary Cap counter clockwise, one click at a time, until a drop of gel appears.
  4. Wipe this first drop of gel away.
  5. Turn again (usually one or two clicks) until more gel appears.
  6. Touch the sensor to the selected area of the test object.

6) Select a gold colour button. 

Depending on the visible colour of the metal you are testing, select one of the following buttons on the unit (see manual for diagram of button locations):

Y-Yellow

W-White

R-Red

G-Green

7) Keep the sensor in a vertical position for about 5 seconds. This is is when the gold value is calibrated.

8) The karat value and European Standard are displayed on the instrument. (Tip: Write this down with a pen and paper you keep to hand, along with your reference for the item).

9) Turn off the instrument.

POINTS TO KEEP IN MIND

1) Electronic tests are not infallible.  If you achieve a result which is outside of expectations then retest in a different location after cleaning your equipment and your item and use new gel. Keep testing until you get a consistent result. Always make a note for the customer if you are selling gold items tested with an electronic tester explain that the test is not infallible and should be seen as a guide only. 

2) Be careful with fine chains. Very fine chains  can be crushed by the dispenser. Avoid pressure with fine gold chains whilst keeping gel contact. It’s recommended to get the results of two or three tests.

3) Be aware of air bubbles. Sometimes air bubbles with give a high or low reading. Always retest and apply common sense to the results of your readings.

4) Clean Tip. A clean tip is essential for an accurate reading.

a) If you are not using the gold tester more than once a week it is advised that you remove the gel tube from the sensor and store it to keep the gel from drying out.

b) Before replacing the gel, whether with a new tube or with one previously removed, clean thoroughly with SC-10 Cleaner Kit. 

c) If the tester has not been used for over a week, clean the tip with the plastic cleaner provided by inserting the tip into the nozzle of the sensor.

d) If gel drops are not dispensed by rotating the twist cap, clean the sensor with the SC-10 Cleaner Kit. 

5) Solder areas and heavy castings with unevenly dispersed metal can give false readings. Always retest in different areas of the piece.

6) Italian Gold may be waxed and can give a false reading. If you suspect the metal may be waxed, clean the testing area with heavy erasing or with nitric acid (only a drop is required).

7) Skin oils can give a false reading. In heavily worn pieces clean the testing area first with the eraser or with non-acetone nail polish remover.

8) Plated Gold. Usually a tiny scratch or a pin prick will allow gel penetration to the base material on plated pieces. If this is not sufficient, two or three tests are recommended with a thorough eraser cleaning in between. If the item is gold plated, the karatage will decrease with each testing. A solid gold piece will not decrease with each test.

9) Dispose of the drop of gel following each test. 

10) Use every other gel drop for best results. 

11) DO NOT LET GEL OR SENSOR NOZZLE TOUCH THE ALLIGATOR CLIP!

12) When removing the cable from the sensor, do not pull the wire! Pull the plug itself to avoid damage. 

13) Testing objects larger than the Alligator Clip. In this instance, unhook the red wire from the testing plate and proceed with the test as per instructions but with the tip of the red wire touching the object.

14) Do not retest the same spot without eraser cleaning.

15) Refer to the manual for full care and maintenance of the tester and follow their recommendations.  

TROUBLE SHOOTING

1) Problem: Brown spot on test surfaces

Solution: Rub the spot with eraser

2) Problem: Display unit reads “NOT GOLD”

Solution: Check the wire contacts and the connections

3) Problem: Display has no reading

Solution: Check batteries or switch to converter or change the wire set.

4) Problem: Inaccurate or different readings

Solution: Keep gel away from alligator clip

5) Problem: Gel does not come out

Solution: Clean sensor nozzle and check gel tube and replace if empty.

6) Problem: Sensor’s rotary cap is hard to turn or is tight.

Solution: Check gel tube and replace if empty.

7) Problem: Changed or reduced karat value on the display from previously.

Solution: Check gel tube and replace if empty.

Copyright © 2017 by Pippa Gaubert Bear and Elder & Bloom. Unauthorized use and/or duplication of this material without express and written permission from this website’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Pippa Bear and Elder & Bloom with appropriate and specific direction to the original content.

Platinum

A Belle Epoque diamond brooch

A Belle Epoque diamond brooch
Modelled as a brilliant-cut diamond pierced openwork coronet of stylised swag design with diamond trefoil and seed pearl alternate terminals, mounted in platinum and gold, circa 1900.
Christie’s Sale 8474

Platinum is a white metallic element that is strong, malleable and ductile; it doesn’t tarnish or corrode. It gets its name from the Spanish Platina del Pinto which means ‘little silver from the Pinto’ (the name of the river in South America where platinum was first found). Platinum is often found in an alloyed state and was first isolated in 1804. In this post, I am just going to discuss a little about the history of platinum use in antique and period jewelry;  I will go into hallmarks and purity in a later post.

A platinum alloy was first developed in 1800 and there were various developments concerning the metal throughout the first part of the 19th century but it wasn’t until around 1870 that the first pieces of jewelry began to be produced using it.  These first pieces of jewelry involved platinum applique only; thin pieces of platinum foil were fused to other metals, usually gold. By 1878, the first platinum tipped prongs were beginning to be used for setting diamonds. As the century came to an end, larger pieces of platinum were used along side gold.

File:Platinum appliqué.jpg

Early Platinum applique. Photo courtesy of Lang’s Antiques.

Brooch

Paris, c. 1890
Platinum, gold, enamel, rose-cut diamonds, rubies, emeralds and sapphires
V&A Museum

Bracelet

New York, c 1890
Gold, platinum bracelet.
Tiffany & Co.
V&A Museum

It wasn’t until the year 1895, however, that platinum really began to be used frequently in jewelry.  This was enabled by the invention of liquid oxygen which allowed for enough heat to melt it.  Jewelers started to really love working with platinum and its strength allowed for fine filigree work and delicate gem setting. Between the years of 1895 until the outbreak of the 1st World war in 1914, platinum jewelry was extremely popular.  Platinum jewelry, often set with diamonds, from that era is thought of nowadays as being very typically ‘Edwardian’ or ‘Belle Epoque’.  Delicate, lacy motifs were popular, and subtle scroll work and curved lines were indicative of the styles of that time. (The Edwardian era is sometimes also referred to as ‘The Garland Era’ in reference to jewelry as the bow or garland motif was so ubiquitous during that time).

A BELLE EPOQUE DIAMOND BROOCH

A BELLE EPOQUE DIAMOND BROOCH
Christie’s Sale 2589

A Belle Epoque platinum, diamond and topaz brooch

A Belle Epoque platinum, diamond and topaz brooch
Christie’s Sale 8127

A BELLE ÉPOQUE DIAMOND AND NATURAL PEARL PENDANT NECKLACE

A BELLE ÉPOQUE DIAMOND AND NATURAL PEARL PENDANT NECKLACE
Christie’s Sale 2604

Precious metals became very scarce during the First World War and jewelery manufacture stopped almost altogether.  It wasn’t really until 1920 that platinum reemerged along side the Art Deco Movement and was used in the bolder, more geometric forms that typified that era.  Once again, the fashion for white jewelry was prevalent, but this time with Art Deco motifs, architecturally inspired lines and styling.  Splashes of color in the form of sapphires, topaz, citrine, emerald and other precious stones were used along side diamonds, rock crystal and paste.  In the mid-1920s, white gold began to make an appearance in jewelry and was soon overtaking platinum as it was less expensive. By the end of 1920, the dominance of all white jewelery reached a peak. Platinum remained the preferred precious metal until 1942 when its use was prohibited by the US government.

An Art Deco platinum, star sapphire and diamond bracelet

An Art Deco platinum, star sapphire and diamond bracelet
Christie’s Sale 8127

AN ART DECO DIAMOND, PEARL AND ONYX BROOCH

AN ART DECO DIAMOND, PEARL AND ONYX BROOCH
Christie’s Sale 5968

A PAIR OF ART DECO DIAMOND AND SYNTHETIC SAPPHIRE CLIP BROOCHES, BY RAYMOND YARD

A PAIR OF ART DECO DIAMOND AND SYNTHETIC SAPPHIRE CLIP BROOCHES, BY RAYMOND YARD
Christie’s Sale 2604

AN ART DECO DIAMOND AND SAPPHIRE BROOCH

AN ART DECO DIAMOND AND SAPPHIRE BROOCH
Christie’s Sale 2589

There are just a few rare pieces from the Retro Era (1935-1945) and most of those were used along side gold. Although platinum was once again legal to use in jewelry after the Second World War, it seemed to have fallen permanently out of favor, never to quite regain the popularity it once had.   My suspicion is that with the prevalence of white gold, people didn’t feel the extra cost of platinum jewelery was worth it.  Also, it seems people will always return to yellow and rose gold as basic precious metals for jewelery because they are easy to visually differentiate from silver.  Today platinum is still used in jewelry, but it is the exception, rather than the rule.

A RETRO SAPPHIRE, RUBY AND DIAMOND CLIP BROOCH/BRACELET

A RETRO SAPPHIRE, RUBY AND DIAMOND CLIP BROOCH/BRACELET
Sale 1393

Sources / further reading:

http://www.langantiques.com/university/index.php/Platinum

http://www.langantiques.com/university/index.php/White_Gold

http://en.wikipedia.org/wiki/Platinum

http://elements.vanderkrogt.net/element.php?sym=Pt

http://www.platinum.matthey.com/uploaded_files/publications/pdf2002/jewellery.pdf

Pinchbeck

Pinchbeck was invented in by Christopher Pinchbeck around 1720 and was guarded as a family secret for many years, although there were many copies. It is a type of brass made from copper and zinc to resemble gold.  It is lighter in weight than gold and stays unoxidized for a very long time.

Pinchbeck’s great benefit was that it brought a gold colored metal to ordinary people.  It was also good for those concerned about theft, particularly when riding on stagecoaches; the wealthy often liked to leave their real gold at home and bring along Pinchbeck replicas.

A GEORGE II PINCHBECK-MOUNTED HARDSTONE CHÂTELAINE WITH NÉCESSAIRE

A GEORGE II PINCHBECK-MOUNTED HARDSTONE CHÂTELAINE WITH NÉCESSAIRE
Christie’s Sale 7800

Chatelaine

Pinchbeck Chatelaine c.1730-1735
V&A Museum

Many pieces throughout the 18th and 19th century are made from Pinchbeck, particularly chatelaines but also a wide range of other jewelry and watches. Pinchbeck was eventually replaced by 9 carat gold in 1854 and electro-gilding in 1840.

Pinchbeck typically comprises copper and zinc in ratios between 89% Cu, 11% Zn; and 93% Cu, 7% Zn.

Today, Pinchbeck is considered quite rare and collectible. It has a distinctive look which you can learn to recognize once you have handled a few Pinchbeck pieces.

Pinchbeck and enamel watch c. 1740
Sotheby’s No8848

A related metal is Bath Metal which is like Pinchbeck but has a higher zinc content (approx 45%)  It was developed also in the 18th century.  It has a white color. It was, however, not used frequently in jewelry.

Sources / Resources:

http://www.langantiques.com/university/index.php/Bath_metal

http://www.langantiques.com/university/index.php/Pinchbeck