This gorgeous ruby and diamond necklace by Cartier, New York, a period piece made around 1938, was put up for auction last year.

At first glance, this piece appears to be just a necklace. However, the three pendants were designed to be detachable and could be worn as brooches. Cartier pioneered the concept of clip brooches which were commonly worn either singly or in pairs. He apparently got the idea after watching a woman hanging up her laundry using clothespegs!

References

Press release : Sotheby's Hong Kong Magnificient Jewels and Jadeite Sale, April, 2006

Leslie Field (1987). The Queen's Jewels : The personal collection of Elizabeth II. Harry N Abrams. Inc