This Metal Education describes the characteristics of three Precious metals which are extensively used in jewelry manufacturing along with tips for their care. By understanding these characteristics, you'll be able to shop with confidence.
Gold is an extraordinary and rare precious metal, with an unmatched combination of chemical and physical properties. It is the only yellow metal and the name gold derives from the Old English word for yellow, 'Geolu'.
Gold is the most non-reactive of all metals and it does not oxidize under ordinary conditions, meaning that it will never rust and never tarnish. Gold's physical properties of high electrical conductivity and chemical inertness make it an excellent and reliable conductor, particularly in harsh environments, where temperatures can range from -55°C to 200°C. No other metal is as malleable as gold. A single ounce of the metal can be drawn into a wire five miles long. Gold is also an excellent conductor of thermal energy. Due to all these specialties, gold is used in various other industrial applications along with jewelry manufacturing.
Gold is widely dispersed through the Earth's crust and is found in two types of deposits:
- Lode Deposits
These are found in solid rock form and are mined by using conventional mining techniques.
- Placer Deposits
These are gravelly deposits found in stream beds and are the products of eroding lode deposits. Since gold is found uncombined in nature, early goldsmiths would collect small nuggets of gold from stream beds etc., and then weld them together by hammering.
Gold's purity is measured in karats. The term ‘Karat’ is different from the term ‘Carat’, which is used to measure weight in gemstones. The purity of gold in karat determines its value. The term ‘Karat’ is derived from ancient bazaars where ‘Carob’ beans were used to weigh precious metals.
Pure gold is very soft and pliable, and alloys of different precious metals are combined with pure gold to enhance its durability and strength, as well as creating a blush in the gold’s appearance with different color tones. 24 karat is 100 % pure gold, and is more expensive and less durable than gold that is alloyed with other metals.
Gold purity for the mostly used Karats:
24 Karat - 24K Gold with 100% purity
22 Karat - 22K Gold with 91.6% purity
18 Karat - 18K Gold with 75% purity
14 Karat - 14K Gold with 58.33% purity
12 Karat - 12K Gold with 50% purity
10 Karat - 10K Gold with 41.67% purity
24 karat gold is soft pure gold without any alloys and it has a deep yellow color and a rich luster. Gold of lesser karats (22K-10K) are all alloyed with a combination of silver, copper, nickel and zinc. This adds strength, but if too much is added (in the case of 10K and less) it can dull the color. For beauty and durability, 14K and 18K gold are highly recommended.
In its pure form, gold has a metallic luster with deep yellow in color, but when mixed or alloyed with other metals, such as silver, copper, zinc, nickel, platinum, palladium, etc. then it creates various color hues like white, pink/ rose, green and the seldom found blue, purple and black.
- Yellow Gold
Yellow gold is the most frequently seen and a timeless color. It is usually alloyed with silver and copper. Depending on the karat gold (14K, 18K or 22K), the color of yellow gold may vary from a softer shimmering yellow to a bright rich yellow. This is due to the varying alloy combinations. The color contrast of yellow gold is most suitable to diamonds and other delicately colored gemstones, as they can appear brilliant and vivid.
- White Gold
White gold is harder than yellow gold with a bright lustrous white color. It is most commonly alloyed with a significant percentage of silver, or a mixture of other white precious metals. Palladium and nickel are other precious metals which are alloyed to create white gold. Due to the presence of nickel in the white gold alloy, it tends to be harder than yellow gold. The percentage of gold naturally varies, according to the quantity of additional precious metal, which is included in the formulation of the alloy. White gold is highly reflective and not subject to tarnish.
- Pink / Rose Gold
Pink / Rose gold is alloyed with copper, and at times possibly even with silver. The proportions are about three parts of 24-karat gold to one part of copper. These alloys blush and accentuate the gold with a pink hue, which varies in color depending upon the amount of copper blended with the pure gold. The quantity of copper determines whether the gold is pink or more rose colored in tone and highlights.
- Green Gold
Pure gold is mixed with silver to get green gold. Although this color is not very popular but still it gives wearer an opportunity to look different.
- Other Gold Colors
To get the blue or black colors, iron is alloyed with pure gold whereas to get purple color, pure gold is alloyed with specific percentages of aluminum, tin, and thorium.
Some examples of alloying formulas to achieve gold color variances are:
18K Yellow Gold: 75% fine gold, 15% copper, 10% fine silver.
14K Yellow Gold: 58.5% fine gold, 29% copper, 12.5% fine silver.
18K White Gold: 75% fine gold, 2 % copper, 17% nickel, 6% zinc.
14K White Gold: 58.5% fine gold, 23% copper, 12.5% nickel, 6% zinc.
18K Green Gold: 75% fine gold, 25% fine silver.
18K Pink/Rose Gold: 75% fine gold, 25% copper.
Raw, un-worked gold pricing is based on the karat ratio and the gold weight. But Gold pricing, in finished jewelry or decorative item, is based on a number of factors, including karatage, gram weight, design and craftsmanship. The techniques of construction can make a piece more durable and flexible for added comfort and it may increase the gold price for that piece. Gold jewelry is mainly produced by machine. Any additional hand finishing or textural interest may also raise the cost.
Solid gold is the most frequently seen gold type available in the market but buyers should also be aware of the other gold types available, which deliver comparable beauty at lower value. Naturally, the higher the gold proportions or weight in the other types, the more expensive they are:
- Gold Filled
It is also known as gold overlay, and refers to a layer of at least 10-karat gold that has been permanently bonded by heat and pressure to one or more surfaces of the support metal, then rolled or drawn to a prescribed thickness. The karat gold must be at least 1/10 of the total weight.
- Gold Plate
Gold Plate refer, a thin layer of plating of 10-karat gold or better which has been bonded to a base metal. The karat gold content may be less than 1/20, but it must be properly identified by weight in terms of total metal content.
- Gold Leaf
Gold Leaf refers, ultra thin gold plating which is pounded and applied by hand to an object. Gold has helped in shaping the course of human history.
Due to gold’s scarcity and beauty, this metal has become one of the most important metals in our daily life.
Platinum is an extremely rare metal, even rarer than gold. Due to its rarity, it is also an expensive metal and it has only been found in a few locations worldwide - Russia's Ural Mountains, South Africa's Merensky Reef and a few small mines in the US and Canada.
Platinum is a strong, dense metal, which allows it to be used in many different ways. Platinum is used in jewelry, laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices. The word platinum comes from the Spanish word ‘Platina’, meaning ‘Little Silver’.
The annual worldwide production of platinum amounts to some 160 tons, compared to about 1,500 tons of gold. The mining and refining processes are both difficult and time-consuming. For example, in order to extract a single ounce of platinum, about 10 tons of ore need to be mined and to get the ore, the rock is crushed, made into slurry, and then mixed with a detergent containing 'collector' molecules. After that, air is blown through the mixture enabling the grains of metal minerals to be separated from the rest of the mixture. This process of refining takes a full five months.
Platinum in jewelry is actually an alloyed group of six heavy metals, including platinum, palladium, rhodium, ruthenium, iridium and osmium. These other metals are so similar to platinum in weight and chemistry that most were not even distinguished from each other until early in the nineteenth century.
Platinum, with its beautiful white luster, is the purest of all the precious metals used for fine jewelry. This grayish white to silver gray metal is harder than gold and very durable with a hardness of 4-4.5 on the Mohs hardness scale, equivalent to the hardness of iron.
Platinum purity is expressed differently than gold. Instead of expressing purity in ratios of 24 parts, platinum standards are expressed as units of a 1,000 parts. The most regular platinum purities seen are:
950 – 95% pure platinum
900 – 90% pure platinum
850 – 85% pure platinum
Platinum is often alloyed with copper and titanium. As compared to gold, platinum requires very little alloy to be combined with it in order to make platinum jewelry. It's the only precious metal used in fine jewelry that is 90% to 95% pure, largely hypoallergenic, and tarnish-resistant. Platinum jewelry maintains its color, brilliance and weight even when scratched, while other metals may lose their luster or become blemished or discolored.
Platinum Vs Gold
Although platinum is quite a new metal as compared to gold but due to its unique properties, it is getting popular very rapidly. Despite its strength, platinum is a very flexible and workable material,
making intricate designs and details far easier to achieve than with gold. Since platinum jewelry contains very little alloy, it is a good choice for those who are sensitive to metals or alloyed gold.
Platinum is also a very dense and heavy metal, so a platinum ring will feel heavier than an 18kt gold ring. Platinum is, however, significantly more expensive than gold. With all other things being the same, a platinum ring will be approximately twice the price of an 18kt white gold ring.
Platinum is extremely long wearing and is very white, so it does not need to be rhodium plated like white gold does. Platinum is normally not used in the full range of jewelry products due to its higher price. Platinum is mainly used in ladies engagement rings, ladies wedding rings and men's wedding rings.
Silver has been known and used for thousands of years and it is considered as one of the three precious metals along with gold and platinum. Pure silver is very soft metal with its lustrous white color. Although it is harder than gold and much more plentiful, but still too soft in its natural state and required to be mixed with a harder metal for the use in jewelry manufacturing. It ranks second in ductility and malleability to gold. It is normally stable in pure air and water but tarnishes when exposed to ozone, hydrogen sulfide or sulfur.
Silver is the brightest reflector of any metal (except for liquid mercury) and can be polished to a high sheen that even platinum can't achieve. It has also the highest electrical and thermal conductivity of all metals, even higher than copper. Most silver is produced as a by-product of copper, gold, lead, and zinc mining. Commercial grade fine silver is at least 99.9% pure silver and purities greater than 99.999% are available. Mexico is the world's largest silver producer which contributed 15% of the annual production of the world. Canada, Peru, Australia and the United States are the other major countries, which are producing silver.
It has long been valued as a precious metal and used in currency, jewelry, ornaments, and utensils. Now-a-days, silver is also used in photographic film, electrical contacts, mirrors, dentistry and surgical implants.
Purity of silver is based on the other metals, which are available in the silver in the form of metal alloys. Unlike gold, but like platinum, silver purities are expressed as units of a 1,000 parts. On the basis of its purity, it can be described as below:
- Pure / Fine Silver
It is the purest form of silver with 99.9% purity. It is also known as fine silver. In this form, silver is too soft to use for jewelry.
Purity - 999 points (99.9% pure silver)
- Sterling Silver
Due to the softness of pure / fine silver, it can not be used in its purest form for jewelry. Therefore, to give strength and durability to the pure silver, it is alloyed with other harder metals, usually copper. A mixture of 92.5% of pure silver and 7.5% of copper is known as Sterling Silver. Sterling Silver is one of the most familiar and used form of silver alloys. Purity - 925 points (92.5% pure silver)
- Coin Silver
A mixture of 90% pure silver and 10% metal alloy is known as Coin Silver. A process of melting down coins done in the 19th century, and mostly discarded today. Purity - 900 points (90.0% pure silver)
- Mexican Silver
Sometimes silver from south of the border is designated ‘Mexican silver’, which consists anywhere from 90% to 99% pure silver.
Silver is very much affordable metal and price of silver is very low as compared to other precious metals. Silver is currently about 1/50th the price of gold by mass. However, its low price allows freedom to silver craftsmen for experiment with new and innovative designs, which are later duplicated in more expensive gold and platinum, once the ‘style’ is safely established
Precious Metals are hard enough and durable in nature but due to our day-to-day activities, it is expected that our precious metal jewelry will get dirty or scratched. Proper care of our precious metal jewelry is very essential to use it for a lifetime.
Here are some tips that will help you to preserve the life and luster of your jewelry’s precious metal like gold, platinum or silver:
Cleaning of Precious Metal Jewelry
On continuous wearing, your jewelry may become dirty as you use various skin and body care regimen such as soaps, lotions and even our skin's natural oils. If you are cleaning your precious metal jewelry by your own then it will take few minutes to clean the same. Regular cleaning of Precious Metal Jewelry is essential to maintain shine of its metal:
- Clean regularly your jewelry’s gold, platinum and silver with soap, water, and a cloth or soft brush, if needed. Simply make a bowl of warm sudsy water with a mild detergent and gently place your jewelry pieces in the mixture. After cleaning, be sure to dry it thoroughly with a soft cloth. Clean tarnished silver with a commercial polish, paste, or tarnish-removing wipe.
- You can also use jewelry cleaners for your precious metals which are sold by many department stores. You can find these jewelry cleaners in kit form. You just need to follow all the written precautions and instructions of cleaning.
- Any grease is removable by dipping the jewelry in any type of alcohol.
- If a piece of silver jewelry becomes tarnished, use a paste, liquid polish or a treated polishing cloth to restore its original luster.
Storing of Precious Metal Jewelry
Storing of precious metal jewelry is also important as a piece of jewelry can scratch other jewelry pieces. Storage of precious metal jewelry needs following precautions:
- One of the best ways to store precious metal jewelry is in a velvet box or in tissue paper. Make sure the metal is dry and is stored in a cool, dry environment. Velvet or tissue paper is used so that other pieces of jewelry that have sharp edges or stones do not scratch or damage the jewelry.
- Precious metal jewelry should be stored in a fabric-lined jewel case or in a box with compartments or dividers.
- Avoid storing your precious metal jewelry directly on wood or plastic.
Wearing Precautions for Precious Metal Jewelry
Precaution is essential at the time of wearing precious metal jewelry. Wearing precious metal jewelry needs following precautions:
- You should not wear precious metal jewelry during rough manual work or activities. It might be harmful as metal get scratched or twisted.
- It is wise to remove your jewelry before bathing, or washing your hands, in terms of safety to the piece of jewelry by slipping off, as well as becoming soiled by the ingredients of soap. The use of soap causes a layer of film to develop on precious metal jewelry, causing its appearance to become cloudy and discolored.
- Avoid the use of chlorine, while wearing your gold jewelry. Chlorine used at high temperatures, is especially harmful to your precious metal jewelry and can permanently harm or damage by discoloring your jewelry, this is good to remember before entering a swimming pool or hot tub, or during housekeeping.
- You should also avoid the situation where your precious metal jewelry comes in contact with hair spray, perfume or other chemicals.
- Inspect your precious metal jewelry regularly for damage or loosening, and have it professionally repaired if the need arises. Even if you do not detect damage or loosening, have a professional jeweler inspect metal jewelry to make sure prongs and bezels remain intact.
- Never put rubber bands or plastic directly against the surface of your silver jewelry.
If you follow the above mentioned caring tips your precious metal jewelry will always shine and luster like a new one.