At one time, black gold meant oil. Now a little less. On the other hand many jewelers have started and make black gold jewelry. But gold isn’t yellow? So how does it turn into black gold? If you want to know what black gold is and how it is obtained, but also how to clean black gold, you are going to satisfied.
In nature, gold is only yellow. Indeed, intense yellow. All the other colors that you can find in a jewel, such as the most common white and pink gold, are the result of particular processes of gold, almost always fusing the yellow metal with others such as silver or copper. Even black gold is the result of particular processes that transform the natural color of the metal. I mean, don’t think there is a black gold mine. So how do you get black gold?
How black gold is made
First method. The most used way is plating with galvanic method. It is the same method that is used for other types of plating: a machine deposits tiny particles of another material on the jewel that deposits like a second skin on the original metal thanks to electrolysis. In this case, rhodium or ruthenium is used. The advantage of this system is that it is fast, inexpensive and has a bright metal. The weak point is that, as in all plating processes, care must be taken not to scratch the metal surface in order not to eliminate the surface layer. Over time, moreover, this superficial part could become opaque and fragile. But it does not always happen, it also depends on the use that is made of the jewel.
Second method. As mentioned at the beginning, gold with a color other than yellow is normally obtained by combining different metals. In the case of black gold, for example, cobalt is often used, which is added to the extent of about 25%. Cobalt is often used to blacken metals, for example for work tools, such as drill bits. The electroplating procedure we have just described is also often used. The advantage: with gold combined in alloy with cobalt there are no scratching problems. On the other hand, if you suffer from a nickel allergy you may also have some problems with cobalt, such as irritating dermatitis.
Third method. Gold does not oxidize like silver, which easily blackens. On the other hand, it can change color if subjected to a powerful laser energy beam. It is not a simple procedure to carry out, because it requires machines powerful enough to intervene on the molecular structure of the metal. So, is this how you get black gold? Yes and no. In theory, jewelry could be made with gold subjected to a laser treatment, but unfortunately it is rather complicated and expensive. Hence, your black gold jewelry is almost certainly not the result of laser treatment.
How many carats does black gold have?
It depends. As with yellow, white or pink gold, the carats depend on the amount of yellow gold used. If the jewel uses the black gold that is obtained in alloy with cobalt, it will have 18 carats if the yellow metal is present for 75%, while if it is 14 carats it means that the percentage drops to 58.3%. It is an aspect to be taken into account in case you want to resell the jewel: it will be evaluated for the percentage of actual gold it contains.
How to clean black gold
Gold is a resistant metal and, especially if it is obtained in alloy with other metals, it does not require special care. You should always avoid putting the jewelry in contact with acid products and, if in contact with the skin, perhaps with products such as creams and cosmetics, it is necessary to regularly maintain cleaning. Particular attention, however, is necessary for jewels obtained with a galvanic process, which are more delicate. To clean the black gold jewelry just a cup of warm water with a couple of drops of liquid soap is enough. After leaving the jewels to soak for about ten minutes, clean them with a toothbrush with soft bristles (no toothpicks or the like to remove dirt). Rinse and dry gently with a cotton cloth. Of course, if the jewel also has pearls or delicate stones (such as opal), caution must be greater.
