Mastery of Design: A Diamond and Stained Chalcedony Brooch, 1912

Diamond, Platinum and Stained Chalcedony Brooch
Cartier, 1912
The Victoria & Albert Museum

After the coronation of King George V, jewelry design began to change from the florid and curvilinear styles popular during the Victorian and Edwardian eras to the sleeker geometric patterns that would define the 1920’s and 1930’s. A new trend in jewelry-making was the love of contrast provided by diamonds and darker stones such as blue sapphires or onyx. The diamonds’ radiance seemed greater when set in platinum next to these more somber stones which exhibited sheen more so than sparkle. Queen Mary was known to enjoy such pieces and had many in her magnificent collection of jewels. Since the Queen was considered a style-setter, elegant black and white jewelry became all the rage.


Due to its popularity, onyx was becoming increasingly scarce at the time. A variety of substitutes were employed to similar effect. Most often used was stained chalcedony. In its natural state, chalcedony has a pale, milky, bluish color. When boiled in a sugar solution, the stone takes on the look of black onyx. High-end jewelers often substitutes stained chalcedony for onyx, stating that, in the long run, the chalcedony was more valuable. The result was actually quite stunning and offered more of a depth and substance to important pieces than would the comparatively flat onyx.

This stunning platinum, diamond and stained chalcedony brooch, made by Cartier in 1912, demonstrates the clever use of this technique. The perfect example of post-Edwardian style, the roots of Art Deco jewelry design can be seen in the dense, close setting of the stones and the play between light and dark.