About the Metals
North Sun Studio jewellery is nickel-free. No German Silver, Nickel Silver, or White Gold are used (nickel alloys).
Copper, Brass, Bronze, Sterling Silver, Titanium, and Gold are all hypoallergenic. The simple definition of hypoallergenic is that contact is unlikely to cause an allergic reaction. Genuine metal allergies will result in the skin turning red, itching, and developing a rash, swelling, or blisters. A sensitivity to a metal (not an allergy) may display a slight irritation or redness. If you typically find that copper-based metals turn green, or sterling silver turns black, this is a result of individual skin chemistry and is not an allergy.
Some metals react with oxygen in the air over time, causing them to oxidize (tarnish). Unlike rust corroding metal, the tarnished layer acts as a barrier protecting the metal from further oxidation. Sometimes metals are oxidized on purpose and then buffed to create contrast in jewellery; these are likely to be treated with a sealant after so the change is not altered with basic cleaning.
Natural oxidation can make some metals appear dark, spotty, or green. Contact with water, salts, and acidic skin can speed the process. Natural copper salts, the same that create the verdigris patina of copper roofs, can be washed off easily from both jewellery or skin. Reduce contact oxidation by wearing jewellery away from areas of perspiration, over clothing, or loosely so there is lots of air-flow. Taking Vitamin D may help reduce skin acidity.
Be sure to give your jewellery basic cleaning (wiping with a soft damp cloth) after wearing and let them air-dry before storage to keep all your metals, stones, and pearls looking their best for years to come!
Metal Colours
From top:
Bronze, Copper, Brass, Titanium, 14K Gold-Fill, Sterling Silver
Copper
Copper is a beautiful warm reddish-orange metal that has been utilized in jewellery for over 7000 years. It can be used as a pure metal, but it can also be mixed with other metals to create alloys with different colours and properties.
An excellent heat and electrical conductor, it is often worn for arthritis, circulation problems, or energy balance. There is no medical proof of its effectiveness with these conditions, however bare unsealed copper is antibacterial, antimicrobial, and antifungal.
Copper naturally oxidizes to a burnt orange-brown, and is sometimes treated with an oxidizing patina solution to get dark tones of brown-black. Jewellery that has been given this treatment is often buffed up, giving additional dimension to a piece by removing the patina from surfaces to highlight them. To keep this patina looking as intended, artists may seal it with clear nail-polish, lacquer, shellac, urethane, or wax. As all of these are coatings, they will wear off eventually. Pieces that have been treated with patina can be cared for with basic cleaning and polishing; if deeper cleaning is done it may remove the patina all the way back to a bare copper colour.
Bare copper will react with acids and salts, causing copper sulfate (a salt) to form on the surface. This copper salt is green/blue, and some artists encourage this process to create beautiful colour or patterns then treat the pieces with sealant to protect it.
Brass
Copper salts are easily rubbed off (they are responsible for green marks on skin that rubs against it). Dirt and oils will hold perspiration (moisture and salts) close to the metal's surface, creating an environment likely to encourage the development of copper salts. As well, copper may react with chlorine in pools or ingredients in some personal care products to form salts (expecially noticable in bends and seams where it can collect). Wiping down jewellery with a soft damp cloth daily, and removing items before activities is recommended.
Brass is an alloy of Copper and Zinc. Natural alloys (not calculated percentages) were in use 7000 years ago, more intentional combinations were being processed just over 2000 years ago, and further refinement developed in the early 1800s. Solid brass has good electrical conductivity, is fairly durable, corrosion-resistant, spark resistant, and non-magnetic.
As an alloy with a large proportion of copper, it has many of the same properties as copper: germicidal, antimicrobial, and will oxidize with moisture and salts to create green/blue copper sulfate that rubs off. These copper salts form a patina that protects the metal underneath from further oxidation. Read about copper salts in the portion at the top of this page.
Bare polished brass is, well, brassy! It is a bright very yellow gold colour which can be quite eye-catching, particularly if your skin tone favours warm autumn colours. Depending on the amount of copper compared to the amount of zinc (65-70%, 35-30%), the colour can range from a rosy yellow to green yellow (more copper means more red tone).
Many prefer brass to be aged a little to tone down the yellow for a richer gold feel. Oxidized brass is a warm brown/green gold, and is valued in pieces with antique looks. Pieces that are ornate can also benefit from oxidizing and buffing to add depth or show off fine details. Brass that oxidizes naturally may have an uneven or spotty appearance, but can be either refreshed or oxidized further quite easily. Artists that have created a piece with a particular look may apply a sealant to either prevent the patina from developing, or preserve a patina. In this case you would not be able to change the look unless you removed the sealant. All sealants will wear off eventually.
Bronze
Bronze is an alloy of Copper and Tin (88%, 12%). This blend of bronze has been in use for 6500 years, its innovation as a workable yet durable metal changed history from the Copper Age into the Bronze Age. The very soft copper and very brittle tin combined properties resulting in bronze being stronger than wrought iron and harder than silver. It's resistant to salt-water corrosion, is spark resistant, non-magnetic, and has high electrical conductivity.
The copper gives bronze antimicrobial qualities, however the oxidation is a little different than brass. For bronze, the changes in colouration are relatively even and predictable, first forming a thin protective patina in brown tone that can become as dark as an old penny, with copper oxides eventually becoming copper carbonate (the green of malachite and azurite). The patina protects the metal underneath from corrosion, skin oils can hasten the formation of copper carbonates (which can rub off onto skin). Read the copper section on wearing copper-based metals.
Most people have experienced the deep rich oxidized colour of bronze seen in sculptures, but are not as familiar with how the metal looks when free of patina. The raw colour of bronze is a soft gold with a hint of pink reminiscent of 10K to 14K gold. Cleaned and polished, it offers an interesting alternative to the expense of precious gold! While this metal tends to gain oxidizing colour quickly, it's relatively easy to refresh. It can also be treated with a sealant to hold the golden tone longer, however all sealants will wear off eventually.
Titanium
Titanium is a relatively new working metal. Discovered in the 1790s, it is an element that occurs in nature only in combinations with other materials, first achieving true isolation in 1910. The processes to successfully extract the metal from raw ore were intensive and continued to develop through the 1940s, when it could finally be produced in commercial quantities. The journey from being a nearly futuristic aerospace metal to finding applications in industry, medicine, and recreation evolved with the fascination of the special properties of the metal. Demand and processing finally made it available for exploration in jewellery-making applications in the 1990s.
Titanium is the 9th most abundant element on earth and can be found in almost all things including rocks, soil, clay, plants, animals, and water. Non-magnetic, non-toxic, and a poor conductor of heat or electricity, it is bio-compatible and an excellent pure-metal option for those sensitive to other metals or metal alloys (like silver or gold). It resists corrosion (saltwater, chlorine, acids, alkalis), will not change colour, is durable, and extremely lightweight (3 times stronger than steel but less than half the weight). Good new for those that don't wear jewellery often (does not feel heavy), and those who are hard on jewellery!
The natural colour of the metal is a silver/white, however it usually appears a soft to graphite grey as it joins with oxygen readily, and this oxidized layer absorbs some of the light reflecting off the metal underneath. The willingness of titanium to interact with oxygen has some interesting benefits: the thin oxidized skin 'self-heals' hiding small scuffs or marks, and it can be anodized to create coloured metal without dyes. Anodization is a controlled electrolytic oxidation where colours are determined by temperature and voltage; the thicker a layer, the more light is interfered with as it travels to the metal surface and is reflected back. Also affecting colour is the finish; commercial jewellery can be given different surfaces from matt to highly polished, however wire jewellery tends to have a matt to satin appearance.
Basic cleaning will keep you pieces in good shape, and a quick buff will refresh the satin sheen when desired.
Sterling Silver
Silver has been in use since at least 4000 BC, however it is very soft in a pure state and not very practical. It is normally mixed with other metals to make it more durable while retaining the qualities and look of silver.
The percent of silver compared to other added metals is often marked as a 3 digit number. Fine Silver is 99.9% pure and would be marked as 999 on a quality tag. In the 12th Century, common Sterling Silver came to have a standard minimum of 92.5% silver (marked as 925) with the balance as 7.5% copper. Developed in the 1990s, Argentium Sterling is marked as 935 with 93.5% silver, 1% germanium, and 6.5% copper. Nickel Silver/German Silver/New Silver do not contain any pure silver at all; they are nickel-based and refer to the colour only.
Positive attributes of silver are that it has better electrical conductivity than copper, is germicidal, inhibits bacteria as well as fungi, has high thermal conductivity, is non-toxic, reflects 95% of visible light (why it shines lustrous white when highly polished), and tarnishes slowly. Silver has such a high reflective quality that sometimes artists intentionally tarnish pieces and then polish the higher surfaces to allow fine details to be seen better. For simplicity, the process still called oxidation even though it is not due to oxygen reactions like copper-based metals.
Silver is stable in oxygen and water, so silver tarnish is a little different than other metals as it reacts instead with sulfur compounds in the atmosphere, creating a yellowish tint or black layer of sulfides. Sometimes people may find that their silver is tarnishing when they are wearing it and the black rubbing off on their skin (similar to the natural copper salts that rub off making skin look green) - this is not an allergic reaction, but changes in body chemistry. All cells contain sulfur, however changes in hormones and some medications may affect the amount contained in perspiration which can accelerate the process where silver is in close contact with moist skin. There are also many daily items that contain sulfur and can discolour your silver if it comes in contact with them including wool, ingredients in some personal care items or cosmetics, household cleaners, and certain foods.
Always use a soft cloth when polishing as silver scratches easily, and care is needed for cleaning oxidized silver as cleaning agents as well as intense polishing can remove it.
Gold-Fill
Gold has been in use since at least 4000 BC, however in its pure form it is too soft for wearing and is alloyed with other metals for durability. The purity of gold is marked in a scale that uses the term karats (K), with 24 karats being the most pure. As other metals are added, the percent of karats decrease: 12K is half of 24K and would therefore be 50% gold with the other 50% an alloy of copper, silver, or other metals. The colour of gold can also be altered from its natural reddish-yellow to reds, greens, white and other colours depending on the blend of the other metals alloyed with it. Gold does not react with oxygen or sulfur (won't tarnish), resists corrosion, and is inert to the body.
The most common karats used for jewelry are 18K and 14K. The reduction of karats gives the gold more strength and it also makes it more affordable while still retaining value. These karat blends can be used as they are, but they can also be used in different production methods: gold-plate and gold-fill.
In gold-plate/gold-electroplate (GP, GEP), an item is dipped into an electroplating solution and the karat grade of gold is deposited as a layer. For items made with a base metal (copper, brass), there is no minimum for how thin the plating may be, and it will chip or flake off exposing the base layer. Items generally cannot be cleaned or repaired. With care, items may last 1-5 years. Vermeil is a thick layer of gold plating (minimum 1.5 micrometers) applied over sterling silver; it usually has a higher karat grade of gold applied and will last longer (it also has an inherent value with both both layers being precious metals).
In gold-fill (GF), a base core (usually brass) is overlaid with a dispersion layer of gold mixed with the base metal, followed by a layer of the karat grade gold that will be the surface. The dispersion layer creates a permanent bond between the base core and the gold top after the layers are heated under pressure and compressed. By law, the layer of gold applied must be 5% of the total weight (1/20th). With normal wear and basic cleaning, it should last 20-30 years (chains will wear faster due to links rubbing). Pieces made with gold-fill can also be repaired with gold. For those sensitive to metal, most people who can wear gold can also wear gold-fill safely.
Usually only a light cleaning with an untreated cloth or mild soapy water are all that will be needed to keep your gold-fill pieces looking great.