A lumachelle and gilt-metal bonbonnière, German, circa 1800

circular, raised thummpiece

one panel cracked on side at 4 o'clock, and minor chips to lumachelle otherwise good condition.
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

Lumachelle is a type of grey marble holding shells that still retain their pearly lustre. There were only a very few sources in Europe, the main one being the mine  of Bleyberg, Carinthia (now South Austria). In the late 18th century - early 19th century, it was considered as 'the most valuable [hardstone] the base [being] a greyish-brown compact limestone, in which are implanted shells of fire colour and beautiful iridescent lustre' (Edward Polehampton, The Gallery of Nature and Art, London, 1818, p. 384).  The hardstone was used frequently to be mounted in pieces of jewellery or snuff boxes, according to the German fashion from the 1760s onwards. Unfortunately, the source was completely extinguished by 1820 so that only small panels were to be found in jewellers' stocks, 'provoking a high demand for this unusual marble.' (Minéraux employés dans les arts mécaniques..., Paris, 1821, p. 450)