One of the most important pillars of quality jewellery making is gold. You’ve probably heard terms like yellow gold, white gold, rose gold, karat, rhodium, but do you know exactly what they stand for and what factors you should consider when making a choice? If the answer is no, we would now like to provide a brief summary to help you for the future.
The history of gold and its most important characteristics
First, a little background from history and chemistry: gold is the best-known and most valuable precious metal found in nature in the elemental state. Scientists believe that all the gold on Earth was formed during supernovae and neutron star collisions, even before the formation of the Solar System.
Gold has been used for thousands of years as a symbol of wealth and beauty before it became a means of payment due to its value and endowments. It served as a currency for a long time and is now widely used in electronics, technology, medicine, dentistry, glassmaking and even space exploration. It is these special uses and the ever-increasing investment demand for gold that make it a highly desirable precious metal beyond the jewellery industry.
The word gold comes from the Latin word aurum, has a melting point of 1064.43 ° C, is liquid in its pure state, and is relatively easy to work with, so it is also used to make precious jewellery.
If you inspect the offerings of more exclusive jewellery stores, you can see that jewellery is made of different colors and shades of gold: in addition to yellow gold, you find white gold, rose gold and even “black gold”. These gain their color partly by their alloy and partly by their surface treatment. Wondering exactly what that means? We'll tell you in a second!
Alloys of Gold
You’ve probably heard of the karat (kt) used to measure the fineness of gold - not to be confused with the carat (ct) used to measure the weight of a diamond. The fineness of gold jewellery is defined by the proportion of pure gold in it, in addition to the various alloys, with pure gold being 100%, i.e. 1000‰. Pure (100%) gold is 24 karats, but it is so soft that it rather unsuitable as jewellery. This is why it is alloyed with various metals such as silver, copper and palladium, which all serve to give the jewellery the right hardness to wear.
In trade, consumers can find out more about the value of the jewel by the number of karats. The gold content of lower karat gold jewelry is proportional to that of the 24-karat pure gold, as follows:
24kt = 1000‰
22kt = 912‰
18kt = 750‰
14kt = 585‰
9kt = 375‰
The fineness mark in the jewellery indicates the proportion of pure gold in parts per thousand, so the 750 mark indicates 18kt gold and the 585 indicates 14kt gold.
The most common fineness in gold jewellery are 18kt and 14kt: premium jewellery brands work primarily with the former, while those in the middle range work with the latter. There is no perceptible difference between them in terms of durability and wearability, in fact only their value differs and hence their prestige.
Considering the above, you can see that the color of gold does not affect either the karat or the price of a particular piece of jewellery. Whiter or rose shades are achieved by using metals of different colors for the alloy, typically silver for white and copper for rose shades, among other material.
Probably the most popular gold color today is white gold. An interesting fact is that it does not reach its “silvery” color immediately after it is produced, as it contains yellow-color gold along with white alloys, and thus has a yellowish-gray base color. To give it a shiny white (more precisely silvery) color, it is coated with rhodium, a precious metal belonging to the platinum family. Similarly, the color of “black gold” is not given by the alloy, but by the “black rhodium” or ruthenium coating. It is important to know that rhodium and ruthenium can wear out depending on the intensity of use, so the surface treatment should be repeated from time to time, especially for jewellery that is subject to more intesnse rubbing (e.g. wedding rings).
Jewellery: Piero Milano, Cervera Jewels, Terzian
How to treat your gold jewellery with care?
A typical question we face is what to look for when caring for our gold jewelry. Fortunately, gold is not a reactive substance, so neither salt water nor thermal water harm it at normal temperatures. It reacts mostly to the “aqua regia”, i.e. the "Royal Water", but we do not encounter this substance in our everyday life.
For home cleaning, you can get a special liquid for cleaning gold jewellery. You should soak your jewellery in this liquid for a few minutes, then clean it with a soft brush and wipe it dry with a fine cloth. Otherwise, warm water with some dishwashing soap and a soft toothbrush are also ideal for cleaning. Be careful, gold is a soft material, it can be easily scratched, and some gems and pearls will not tolerate chemicals, so in some cases it is better to use only a damp cloth, possibly with a small amount of dishwashing liquid on the gold parts.
More thorough cleaning, polishing and surface treatments should be left to a specialist, ideally every year or at least biannually. As always, we stay at your disposal for this service as well.
Jewellery: Mattioli, Aruba collection
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