Stainless Steel
Stainless steel is an alloy of steel with chromium, and sometimes another element such as nickel or molybdenum.
Its resistance to rusting, corrosion and staining, relatively low cost and maintenance, and recognizable luster make it an ideal base for watches.
Stainless steel also will not oxidize or turn black, and is receptive to such finishes as brushed, matte and satin.
Platinum
Platinum is a grayish-white metallic element found in very few places around the world; in fact, it's considered 30 times more rare than gold. As such, it's a more expensive metal, but unequalled in terms of durability and resistance to wear, making it a perfect choice for producing jewelry and watches that last a lifetime.
Platinum is also pure, naturally white and kind to the skin. It never fades, tarnishes or needs to be replated, and is inherently hypoallergenic.
Remarkably pliable, yet heavier and stronger than other precious metals, platinum can also be drawn out into a fine wire, allowing it to be formed into such intricate items as mesh.
Also important to note, is that while platinum is more malleable than gold and can scratch, it does not change shape or abrade like gold. Therefore, over time, platinum settings last longer than gold ones.
Gold
Gold is a yellow metallic element with excellent malleable and ductile properties that make it one of the most popular choices in the fabrication of jewelry and watches.
Pure gold is quite vulnerable to softness and scratching, however, so it is usually mixed, or alloyed, with other metals to increase its hardness.
Karat (or K) measures the proportion of pure gold that's mixed with other metals to create the final metal. The higher the proportion of pure gold used in the final metal, the more valuable and expensive (and also the softer) the gold will be. Therefore, an 18-karat gold watch will be more valuable, expensive and softer than a 14-karat gold watch.
Mixing pure gold with other metals not only hardens it, but also influences its color. Pure gold, or 24K, is always the most yellow, with a beautiful, warm hue. Due to its softness, however, one common practice is to plate harder, lower-karatage gold such as 14-karat, with a softer, higher-karatage gold such as 18-karat, to achieve the brighter yellow.
Rose gold, on the other hand, is pinkish in color, created by alloying gold with the red-colored metal copper. Although the names rose gold, pink gold and red gold are often used interchangeably, the difference lies in the copper content: the higher the copper content, the stronger the red coloration.
Apart from copper, all other alloying metals tend to bleach the color of gold, resulting in what's commonly known as white gold. In practice, nickel and palladium (from the platinum family) are strong "bleachers" of gold, silver and zinc are moderate bleachers, and all other alloys are moderate to weak in effect.
This has given rise to two basic classes of white golds: the nickel whites and the palladium whites. Unfortunately, however, many people, especially women, are allergic to nickel when it comes in contact with the skin, so in some parts of the world, jewelry and watches containing nickel are being phased out and replaced with the more expensive palladium white gold.
White gold is also frequently plated with rhodium, a rare and more expensive metal from the platinum family, to create a whiter, brighter finish. The rhodium does wear away, however, and should be reapplied periodically by a reputable jeweler.
Another consideration with white gold: while it's harder and more resistant to scratches than platinum, itos more brittle and susceptible to stress corrosion than both platinum and yellow gold.
Titanium
Titanium is a silvery-gray metallic element that's not only light but also strong; in fact, it has the highest strength-to-weight ratio of any metal. Titanium products therefore can be significantly lighter without compromising strength.
Sometimes called the "Space Age Metal," titanium can be mixed with such elements as aluminum, iron, molybdenum and vanadium to produce strong, lightweight alloys for jewelry and watch applications. It can also be attractively colored.
In addition, titanium has excellent resistance to dents and corrosion, including corrosion due to seawater and chlorine, making it useful in the production of watchcases.
Titanium's inertness also makes it a good choice for those with allergies.
Ceramic
New techniques in producing ceramics have resulted in a high-quality, extremely hardy substance suitable for watchmaking.
Valued by watchmakers for its lightness and durability, high-tech ceramic is also scratch-resistant, thin and smooth to the touch.
