The use of small sections of rock-crystal threaded on wire supports was one of the most striking innovations in lighting of the 17th Century. Rock crystal was principally worked in Milan but it was French designers who developed the idea to its fullest splendour. Four immensely impressive examples of this type are visible in a print of the King's Bedchamber at Fontainebleau in 1654, reproduced in P. Thornton, Seventeenth Century Interior Decoration in England, France and Holland, Yale, 1978, pl. 33. By 1670 cheaper and simpler imitations were being produced in France but rock crystal was still used until after the end of the century (ibid., p. 275).
A chandelier of this type at Penshurst Place, Kent, is illustrated in R. Edwards and P. Macquoid, The Dictionary of English Furniture, rev. ed., London, 1954, vol. I, p. 330, pl. 9.