At the start of the 1940s the jewelry arts were interrupted by the onset of World War II. Precious metals, especially platinum, were rare and in some instances forbidden to be sold. Palladium was substituted for the platinum being used in the war effort. In order to eek the most out of the available gold, a low karat gold alloy was used with a higher copper percentage. This resulted in gold with a subtle but distinctive reddish tinge, indeed through the cunning use of alloys, gold appeared in multiple colors within a single piece. Gold was manipulated in various ways; woven, braided and coiled. Resilla, cannetille and lacy filigree patterns reappeared in jewelry. Various textures were juxtaposed within a design putting matte finish next to bright to accentuate the design. Gold became the quintessential jewelry metal of the 1940s and 50s.
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.
Because of the softness of pure (24k), it is usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Alloys with lower carat rating, typically 22k, 18k, 14k or 9k, contain higher percentages of copper or other base metals or silver or palladium in the alloy. Copper is the most commonly used base metal, yielding a redder color.