Art Deco, the first international style that originated in Paris in the 1920s, appeared through the design of interior and exterior spaces and the styling of clothing and jewelry. Art Deco displays admiration for the machine's modernity and the inherent design elements of manufactured objects (like symmetry). This also applies to jewelry. Strong geometric designs, bold gemstone colors like emeralds, rubies, and new materials like platinum dominated. Art Deco diamond rings are the safest option if you like symmetry but don't like the bold colors that are typical for that era.