What is a Karat?
When gold is mixed with other metals, the gold content of alloys produced is expressed in karats. Karats (also spelled carat, but should not be confused with the unit used to measure the weight of gems, which is also called carat) is a measure of the fineness (i.e., purity) of. gold. A gold karat is 1/24 part (24ths), or 4.1557 percent, of the whole and the purity of a gold alloy is expressed as the number of these parts of gold it contains. At 24 karats, gold is pure whereas as 18-karat gold contains 25 percent of other metal and a 12-karat gold alloy are 50 percent gold. Gold karat is symbolized by the letter “K” (while carat, the unit for measuring precious gemstones is represented by “ct”.)
The table below gives us the differing qualities of gold accenting to its karat.
Different Qualities of Gold, According to its Karat
- 24-karat gold -100% pure gold
- 22-karat gold – 91.7% gold, 8.3% another metal
- 20-karat gold – 83.3% gold, 16.7% another metal
- 18-karat gold-75% gold, 25% another metal
- 14-karat gold – 58.3% gold, 41.7% another metal
- 12-karat gold – 50% gold, 50% another metal
- 10-karat gold-41.7% gold, 58.3% another metal
- 8-karat gold – 33.3% gold, 66.7% another metal
- 6-karat gold – 25% gold, 75% another metal
The Process of Melting Gold and Silver
Metals are generally melted to obtain certain desirable changes in its nature, form, size, and shape. Melting decreases or relieves internal stresses or reduces the solid metal objects into liquefied metal.
When melting a metal to make jewelry, the desired amount or percentage of gold, silver, or any other metal to be used is placed in a special container, called annealing dish; the dish is placed over the fire with the use of a gas tank and compressor. The process of heating a metal is called annealing (the treatment of a metal or alloy by heating to a predetermined temperature to improve its ductility and reduce brittleness). The heating process is done until the metal is liquefied and turns reddish as the color of a glowing ember.
Basic Methods of Jewelry-Making
Jewelry-making requires different methods and steps in preparing the metal-silver or gold-to be used. Each step is a process in itself. The basic methods are as follows:
- Melting and Sheet Casting – the process of melting a metal (silver or gold) to be used in making the jewelry.
- Sawing and Cutting – the process of cutting a piece of gold or silver according to the desired size.
- Soldering and Assembly – the process of joining the metal surfaces and/or attaching together several pieces of metal being worked on to attain the desired form.
- Filing and Forming – the process of shaping a metal into desired form and then, with the aid of a file, the edges and corners of the shaped metal are polished.
- Stonesetting and Engraving— the technique of inserting or mounting precious or semi-precious gemstones into the metal setting of the jewelry. For instance, silver is frequently used for diamonds to make the setting less visible.
To enhance the color and brilliance of gold or silver jewelry just made, it is subjected to plating or electroplating by dipping the jewelry into a plating solution.
Basic Tools in Jewelry-Making
The following basic tools are needed:
- Holding tools, such as: pliers, tongs and tweezers
- Cutting tools, such as: a jeweler’s saw, blade, craft knife and a pair of scissors
- Shaping tools, such as: graduated ring mandrel, graduated ring size, draw plate, anvil, roll press, rounding block and bar, dapping dice and mallet hammer
- Soldering equipment, such as: a torch and blower set, annealing dish, gold or silver solder
- Filing and polishing tools, such as: polishing motor, felt buffing cone and nylon-bristle brush
source: TRC Business Guide, www.trc.dost. gov.ph, photo from www.freedigitalphotos.net