清十八 / 十九世紀 寶石藍料灑金星鼻煙壺

Hugh Moss、Victor Graham 及曾嘉寶，《A Treasury of Chinese Snuff Bottles: The Mary and George Bloch Collection》，卷5，香港，2002年，編號722

Suffused with tiny air bubbles, many of which have burst at the surface. Some minor surface wear and a tiny scratch on the foot.
"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."

This is an example of the so-called ‘sandwiched-glass’ group, in which a decoratively prominent and usually predominant layer of colour is contained between two other layers of glass, the upper one transparent to enable the middle layer to be seen. They represent an additional level of complexity in the production process when compared with single-colour glass or glass with fragments rolled into the surface of another colour. They are created by taking a gather of glass of the inner colour on the blow-iron, decorating its surface in some way (here with the addition of rolled-on tiny flakes of biotite) and then adding an outer layer of transparent glass. This further complication of the process made possible a variety of new and intriguing decorative possibilities.

The inclusions here have been identified by Heiner Schaefer as biotite - a form of mica that can be ground into tiny flakes and trapped between two layers of glass. If the mica is of coppery or golden colour it is known as biotite, while the silver variety is muscovite. Since biotite was found in the Bavarian forests, the process may have been familiar to Kilian Stumpf, although it is not known whether or not  it was used so early in Bavaria. It is also found elsewhere, however, and European glassmakers are the most likely to have been responsible for its introduction to China. In this example, the colour resembles aventurine-glass, but under magnification it becomes evident that the inclusions are a series of discreet flakes. The irregular, rough-edged biotite has created an intriguing effect by trapping large, irregularly shaped air bubbles. If irregular solid flakes of some sort are sprinkled or in some other way introduced onto the surface of a piece of glass that is then cased with another layer of glass, some trapped air is inevitable. The surface tension of the air bubbles has become attracted by the biotite flakes and stretched the air into unusual, jagged shapes, making them even more prominent as the light is reflected from their irregular surfaces.

Cased or overlaid glass of this sort, whether containing a sandwiched layer or not, originated during the Kangxi period. A set of twelve cups presented to the throne in 1708 by Ding Zaobao 丁皂寶 (probably a high-ranking eunuch) appears to have consisted of at least two layers of glass. The carver, a man from Guangzhou named Cheng Xianggui 程向貴, may have been working either at the imperial glassworks or in a separate facility run by Ding Zaobao—the latter possibility is suggested by the facts that 1) Ding had an uncarved set made by another Guangdong craftsman that he didn’t present to the throne until 1724, and 2) when a query came down in late 1725 as to the particulars of the production of the two sets of cups, only Ding Zaobao knew that the two glassworkers had returned to Guangdong in 1715. On a glassworks run by a contemporary prince, see Sale 3, lot 100.