In many cultures, rings are a symbol of marriage, status, friendship or other close relationships. They may also serve as talismans or amulets. They can be very personal, such as those engraved with an inscription or a small piece of jewelry; they may be purely decorative, such as the bangles worn by many women; or they may have a more practical purpose, such as the poison rings, which functioned as talismans for suicide or homicide, and were sometimes made to contain a poison for purposes of self-inflicted death or as a way of concealing a deadly weapon. There are even rings with bezels that open, which might have held sentimental keepsakes in miniature.
Historically, men and women have worn rings to symbolize their social or professional status, such as a ring bearing a coat of arms or a badge or medallion. Some societies have worn rings as signs of membership in their religion or a secret society. For example, Masons wear a distinctive ring with an eponymous symbol on the top. In Western culture, a wedding ring is the traditional symbol of marriage, although engagement rings have become more common in recent decades. The ring is also used as a sign of friendship, and some people wear rings to show their support for causes they care about.
A ring is also a mathematical object. The term refers to a set of numbers that has an addition that is commutative and associative, the identity element zero, negatives of all elements (to form the ring’s multiplicative inverse), and two distributive laws relating addition and multiplication (a(b)c = ab + c for any a, b, and c). A ring can be either commutative or non-commutative; the former are called ordinary rings, the latter are called cyclic rings.
Most rings are made of gold, silver, platinum or palladium, and they can be polished or hammered to produce a more decorative or shiny appearance. Other metals that are used to make rings include titanium, tungsten carbide and stainless steel. The harder metals are less malleable, and they must be treated carefully to prevent damage. Titanium and tungsten carbide have the added benefit of being hypoallergenic. In addition to being hard, these metals are also relatively lightweight.
Many people wear multiple rings, and they can be stacked in a variety of ways. One popular option is to wear a ring on each finger, including the thumb, so that there are matching rings on all four fingers. Some people also coordinate rings to suit their mood or style. For example, they might wear a gemstone ring on the ring finger and a simple metal ring on the thumb to create contrast.