Opals were discovered in 400 BC, and since then five types have been found throughout the world. Before you start shopping for these mysteriously beautiful gems, learn about the different varieties — and find out which historical figure was reportedly willing to trade his kingdom for a single stone.

The European Fine Art Fair is heading to Manhattan this weekend, and we have a preview of the incredible pre-1920 offerings of fine and decorative art from top dealers.

Art Deco style, with its emphasis on gilded details, geometric shapes and rich materials, is still favored by designers looking to infuse interiors with an air of luxury and sophistication.

Interior designer Katie Martinez offers professional advice on picking a carpet for any room.

Details are everything in these spaces, where the interior designers knew that a bold area rug, sumptuous upholstery or striking artwork would take a living room to the next level.

It's the best of both worlds — distinctive architectural details setting the stage for a mix of contemporary, vintage and antique furnishings. The resulting spaces are artfully eclectic, both stylishly edgy and comfortably classic.

The stone of choice for Napoleon, Princess Diana and Elizabeth Taylor has been a favorite of aristocrats and the well-to-do since the time of the Ancient Greeks. Learn how to shop for the bright blue gem, and why it's chemically impossible for a sapphire to turn red.