A 5.61 carat oval London blue topaz with 0.11 carats of round Swiss blue topaz in 18K yellow gold over sterling silver pendant on an 18-inch Singapore chain - the pendant where the richest and the brightest blue topaz varieties work together. London blue is the deepest and most saturated of the topaz blues - a rich inky blue with green secondary hue; Swiss blue provides a brighter, lighter counterpoint. Together in warm gold, the combination creates a blue story with depth and variety. Lobster claw clasp.