Greco-Roman
Greek literature indicates jewelry played a big role both as adornment and as a sign of wealth as far back as the fall of Troy. Greek jewelry was rich and varied, reflecting the society's prosperity.  This period included crowns, earrings, bracelets, rings, hairpins, necklaces, and brooches. Pendants were a special favorite. Greek ladies sometimes wore necklaces with a variety of pendants often 75 or more dangling miniature vases, each ornamented with filigree or 14K gold flowers or animal figurines.
 

From the twelfth to the fifteenth centuries, except for nobility, few wore jewelry. During the Medieval period, styles and morals combined to discourage jewelry. The religious cross pendant was very popular.  Ordinary medieval costume was simple, often of heavy, dark wool with a brooch or clasp at the neck along with jeweled belts of every kind. Hatpins became an accepted part of men's wear. Necklaces and earrings were uncommon, but rings bearing religious jewelry symbols and inscriptions were popular. Every one wore rings, from lower class to nobility. Rings were made of iron, copper, sterling silver or gold. The material of the ring often denoted the wearer's social class.  Faceted stones did not appear in rings until the 14th century.

Medieval - Renaissance

In the late Medieval period, a little more jewelry begins to appear.  Necklaces make an appearance, but mostly as collars.  Collars had become elaborate affairs with complicated twists and beads.  However, rings were the dominant adornment of choice.  Men and women alike often wore rings on all ten fingers.  The rings of the Renaissance began to take on more of a symbolic reference;  Rings of the period fall into four categories:

Ecclesiastical rings - as sacred emblems of the Church
Curative rings - thought to cure ills of the body, soul, or estate 
Rings of romance and sentiment - for betrothal, weddings, love, friendship, to express loyalty to a hero, or mourning
Fancy or gadget rings - the pugilist's ring (like "brass knuckles"), compass rings, puzzle rings, and tobacco stoppers (for filling pipes).

Elizabethan

During the Elizabethan period various sorts of jewelry began to appear. Elizabeth I had an even more consuming passion for jewels. Her wardrobe included 2,000 dresses, each weighted down with jewels.  With pearls as her trademark, Elizabeth's taste for dress ornaments was typical of the Renaissance.  Earrings were first introduced in Italy – At that time, they where were most often plain drop pearls with simple matching pearl choker. A variation on the pearl earring is the pearl drop suspended from a ribbon that meant to accompany the clothing.

17^th Century

The seventeenth century was the era of baroque design, reflecting the parallel renewal of classicism. (The term baroque, possibly from the Portuguese baroca, for misshapen pearl, was used by later critics to disparage the styles of this century.) Emphasis shifted from multicolored, enameled objects to glittery, gem-studded items, after the introduction of stone faceting. Although emeralds, rubies, topazes, and sapphires were all, popular, diamond was the most sought after. Floral motifs were widely used as well as ribbons, bows, stars, and knots. These themes, with an emphasis on lighter, more open jewelry, continued through the century.

18^th -19^th Century

Fancy hairpieces called aigrettes, highlighted towering hairstyles. The parure, a matching set of jewelry, came into fashion. It often included a sevigne brooch, girandole earrings an aigrette and a necklace, bracelet, or stomacher. Although ladies wore most of the diamonds, some upper class men sported diamond-studded waistcoat buttons, shoe and belt buckles, cufflinks and ceremonial badges.  The eighteenth century saw a further decline in colored enamels and an increase in the use of diamonds and other faceted gems. Jewelry design followed fashion to the rococo style, marked by scrolls, curlicues, asymmetrical masses, and gimcrack detail
 

Art Deco

The period also known as the Roaring Twenties saw a huge demand for jewelry, and a new style made its appearance at an event in Paris, the Exposition Internationale des Arts Decoratifs et Industriels Modernes. This new design style took its name from that fair, now known as "Art Deco" – Art Deco is a wonderfully decadent period stylized by intense color, bold color combinations, and well-defined geometrical designs typified Art Deco. In jewelry, stones of complementary colors were often set in a single piece.

Modern

Jewelry as an art form had not been so lively since the fifteenth century.  Today international jewelry design has taken many directions- almost anything goes. No single set of artistic conventions dominates the scene in our "post-modernist" age. Designers and crafts people are turning out highly individual creations.  There are some prominent influences. Like their compatriots in the apparel industry, Italian jewelry houses have gained a worldwide reputation for elegant styling in luxurious materials. Modern Scandinavian design has a clean simplicity, particularly in silver. Recently the Japanese have begun to make an impact in the fashion world with their boldly articulated lines and forms.

In the last few decades, several styles have seen a revival reflected in jewelry design. In the U.S. the rediscovery of Native American crafts accompanied the "hippie" counter-culture of the 1960s.  By the early 1970s, sterling silver and turquoise jewelry and Native American motifs like the squash blossom was all the rage.

Then the highly publicized American tour of the treasures of Tutankhamen (1976-1978) led to a brief revival of ancient Egyptian motifs in commercial products, including jewelry. Art Nouveau and Art Deco styles have seen a popular revival in recent years. And there have even been some reinterpretations of the early Byzantine style in fine jewelry design.

By the 1940s still another design was introduced, called "Retro Modern," that featured flamboyant curves and bows in large pieces of jewelry. Yellow, pink and even green gold was used in this jewelry, along with unusual mixtures of colored gemstones. Today's consumers look upon this style as garish.

World War II created a shortage of platinum, so most jewelry was made of gold, sterling silver and cubic zirconium, but platinum made a huge comeback in the early 1990s. Such pieces as the tennis bracelet and diamond solitaire pendant made their debuts during the latter part of the 20th Century thus increasing the popularity of designer jewelry.