Art Deco received its moniker from the Exposition International des Arts Décoratifs et Industriels Modernes, held in Paris in 1925, which was largely dedicated to the jewelry arts. Emphasis was placed on the association of art and modern industry. Inspiration for this style was as far reaching as Oriental, African and South American Art and as varied as Cubism and Fauvism, both popular movements at the time. The term "Cubism" was often used to describe jewelry of this era because of the angles, geometric lines and figurative representations used in its execution. A desire to eliminate the flowing lines of Art Nouveau and distill designs to their rudimentary geometric essence, thus eliminating seemingly unnecessary ornament, resulted in the cleaner and more rigid lines employed in Art Deco jewelry. A look forward toward modernism and the machine age also featured prominently at this juncture in jewelry history.
During the Art Deco era, advancements in cutting techniques, including the advent of the modern round brilliant cut style, allowed for diamonds to become more dazzling and scintillating than ever before. Meanwhile, prosperity was permitting more people to afford diamond jewelry and engagement rings. New casting techniques further increased accessibility, as jewelers discovered more efficient ways to produce the most intricately detailed of settings.
Onyx is the name for the black and white banded variety of chalcedony. It has been used since antiquity when it was highly prized as a cameo stone. The layered color structure allows the engraver to cut the subject in one color while creating a background of another. The term onyx is often encountered describing pure black material although this is technically incorrect.
Topaz is a gemstone which, throughout history, has shared its name with all other yellow gemstones. It was not until the mid 18th century that the name was assigned to the aluminum fluor-silicate that is uniquely topaz. During the 16th century Cellini described a (most probably) yellow sapphire as "topaz". Due to its close resemblance in color to citrine, yellow to orange "actual topaz" were termed "precious topaz" to distinguish between them. Topaz comes in many hues, from colorless to yellow, blue, brown, red and everything in between. The colorless and pale blue stones are most abundant in nature, followed by yellow and brown stones, while the golden-orange, pinks and reds are most rare. The latter are mostly mined in Brazil.
Marcasite is an iron sulfide mineral with an orthorhombic crystal structure. It is very brittle and unsuitable for jewelry. What we call "marcasite" in jewelry is actually Pyrite – "fools gold" – that has been faceted to imitate diamonds. Popular from around 1700 onward, marcasite is usually found mounted in silver. Because of its golden yellow color and metallic luster, Marcasite has remained popular in higher quality fashion jewelry. In antique jewelry, marcasite can be distinguished from cut steel faux gems because marcasites are usually bead or prong-set as a gemstone would be and cut steel is riveted.
Silver is a white metallic element, harder than gold, softer than copper and second only to gold in malleability and ductility. Represented on the Periodic Table of the Elements by the symbol Ag, silver is an excellent conductor of heat and electricity. Silver is considered one of the noble metals because of it is excellent resistance to oxidation. Historically, silver has played a prominent role in the production of jewelry an objets d'art and is usually alloyed with another metal to harden it enough to maintain the desired shape and details imparted to it.