A striking colored-diamond ring is the star of Christie’s upcoming ... and diamond brooch ($100,000 to $150,000) and a rare JAR ruby and diamond torsade necklace ($80,000 to $120,000).

Regine Ngan, managing director for Asia, admires the Crimson Flame, the brand's pigeon's blood ruby ring ... Flame in a white-gold ring, engirdled by cushion-cut diamonds. It was in this form ...