An engagement ring is a ring indicating that the person wearing it is engaged to be married, especially in Western cultures. In the United Kingdom, Ireland and North America, engagement rings are traditionally worn only by women, and rings can feature diamonds or other gemstones. In other cultures men and women wear matching rings. In some cultures, engagement rings are also used as wedding rings.

Conventionally, the woman's ring is presented as a betrothal gift by a man to his prospective spouse while he proposes marriage or directly after she accepts his marriage proposal. It represents a formal agreement to future marriage. Rings can be bought by the man, the woman, the couple together, or by each partner for the other. In North America and the United Kingdom, it is customarily worn on the left hand ring finger. Similar traditions purportedly date to classical times, dating back from an early usage reportedly referring to the fourth finger of the left hand as containing the vena amoris or "vein of love". This custom may have its origins in an ancient Egyptian myth that the finger contained a vein leading directly to the heart, or it may simply be because the heart lies slightly to the left side of the body. In Ukraine, it is customary for the ring to be worn on the right hand. In Germany the ring is worn on the left hand while engaged, but moved to the right hand when married. In Poland, the engagement ring and wedding band are traditionally worn on the right hand but modern practice varies considerably. Before agreeing to marry, a couple may choose to buy and wear pre-engagement rings, also called promise rings. After marrying, the couple may wear both engagement rings and wedding rings, or just their wedding rings, as they prefer. Some brides have their engagement and wedding rings permanently soldered together after marriage.

A finger ring is a circular band worn as a type of ornamental jewelry around a finger; it is the most common current meaning of the word ring. Other types of metal bands worn as ornaments called rings, such as arm rings and neck rings. Rings worn by both men and women and can be of any quality. Various ring shapes and styles exist. The following are but a few. Flat wedding bands are the simplest form of ring. A flat wedding band consists of a strip of metal bent around into a loop and joined where the ends meet. Half-round rings, also called D-shape rings, are flat wedding bands filed half-round on the outside.

Sleeve rings are rings that consist of a thin inner ring or sleeve, with several other rings stacked onto it to form one solid ring. Either the rings soldered onto the sleeve or the ends of the sleeve can be upset to keep them all together. A little of both can also be done. Solitaire rings are rings with a single large stone as a centerpiece, usually a diamond. Eternity rings are rings with stones, usually diamonds, of the same cut and size, set in one row all around the ring. The stones are usually round or square, and the setting is usually either claws or a channel setting. When the stones do not continue around the entire ring, but stop halfway around the finger, it is a half-eternity ring. Trinity rings or Trilogy Rings are three rings worn at one time. Cluster rings are rings with a group of stones in a cluster setting, forming the focal point of the ring. The cluster setting usually consists of one large stone in the center surrounded with several smaller stones. Tension Rings are a type of ring in which a single gemstone is held in place by pressure rather than prongs, a bezel or other mounting. The metal setting is actually spring-loaded to exert pressure onto the gemstone. In the United States and Canada, ring sizes specified using a numerical scale, with quarter and half sizes. An increase of a full size is an increase of 0.032 inch in diameter, or roughly 1/10 inch in inside circumference. Generally, sizes in quarters and halves will not relate conventionally to anything on any known ruler. On one finger alone, a person may vary more than a whole ring size- depending on time of day, work performed, and other swelling-inducing activities/conditions. Therefore, in most cases quarter-sizes are meaningless unless one needs precise accuracy with a particular ring.

Emeralds

Emeralds, like all colored gemstones, are graded using four basic parameters – the four Cs of Gemstones: Color, Cut, Clarity and Crystal. The last C, crystal is a synonym that begins with C for transparency or what gemologists call diaphaneity. Before the 20th century, jewelers used the term water as in a gem of the finest water to express the combination of two qualities, color and crystal. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emerald, crystal considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency considered a top gem. In the 1960s, the American jewelry industry changed the definition of emerald to include the green vanadium-bearing beryl as emerald. As a result, vanadium emeralds purchased as emeralds in the United States recognized as such in the UK and Europe. In America, the distinction between traditional emeralds and the new vanadium kind reflected in the use of terms such as Colombian Emerald. Scientifically speaking, color divided into three components: hue, saturation and tone. Yellow and blue, the hues found adjacent to green on the spectral color wheel, are the normal secondary hues found in emerald. Emeralds occur in hues ranging from yellow-green to blue-green. The primary hue must be green. Only gems that are medium to dark in tone considered emerald. Light-toned gems known by the species name, green beryl. In addition, the hue must be bright (vivid). Gray is the normal saturation modifier or mask found in emerald. A grayish green hue is a dull green. Emerald tends to have numerous inclusions and surface breaking fissures. Emerald graded by eye. Thus, if an emerald has no visible inclusions to the eye it considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated, oiled, to enhance the apparent clarity. Eye-clean stones of a vivid primary green hue with no more than 15% of any secondary hue or combination of a medium-dark tone command the highest prices.6 This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut into cabochons, rather than faceted shapes.