Watch cases, the housing of the timepiece that contains the internal movement, can be made out of anything that’s durably solid, but today’s cases are primarily made of stainless steel. Stainless steel is quite durable and contains a bit of chromium to help protect the steel from corrosion and rust. Typically silver in color, it can be plated with a thin layer of gold (about 10 microns, or 1/1000 of a millimeter in thickness) in whole or in part for added accent. You can also find stainless steel cases in different colors, thanks to a process called ionic plating or PVD (physical vapor deposition) which usually gives it a matte finish.
The most popular form of gold is still yellow gold, but rose gold, featuring a pinkish tint due to a higher concentration of copper in its alloy mix, is gaining in popularity. When shopping for gold watches, pay attention to the fineness (or purity) of the gold as expressed in karats. A single karat equals 1/24 of the pure metal, so an 18 karat gold watch translates to 75 percent pure gold (whereas 14 karat gold equals 58 percent).
Titanium has become popular in higher-end watches as it’s a bit more expensive and harder to work with. Offering a lighter shade of silver, titanium is 50 percent lighter than steel, but 30 percent stronger. For watch enthusiasts who have allergic reactions to stainless steel, titanium is an excellent alternative as it doesn’t contain nickel (the allergen found in stainless steel). It’s also a great choice for diving and water sports as it’s very resistant to salt water corrosion. On the downside, it’s a bit more apt to picking up scratches.
Additionally, you’ll find watch cases made of precious metals, such as platinum (used in luxury watches) and sterling silver, ceramic, tungsten, aluminum (also very corrosion-resistant), and carbon fiber. Sport watch cases are typically made of hardened rubber, plastic, or resin, and are a good option for use during more rugged activities.
Wrist watches come in a few basic shapes: round, square, and rectangular. A fourth popular shape is Tonneau, which has a tall orientation with a flattened top and bottom, and bulging sides that resemble a barrel. Round watches are the direct descendent of the pocket watch and are the most popular shape. The majority of sport watches will be circular as it’s the shape that’s easiest to make water-resistent. Square watches provide more of a canvas for adding decoration to fashion watches. Rectangular watches are considered dressier as they can be better hidden under the sleeve. Tonneau-shaped watches present a unique retro style and are also considered dressy thanks to their slimmer profile.