Apart from fitting the bottle perfectly, thehandsome lapis lazuli stopper is of a type that was produced at the Palace workshops during the Qianlong period and the fact that it is composed of two materials, a rather complex job for a simple stopper, is typical of the Palace workshops, where pieces might be sent from one shop to another to have bits added, special boxes made, lids carved, gilt-bronze details made, and so forth.
Although of an elongated ovoid form, this shape is also inspired, or at least makes reference to, the standard meiping ('prunus-blossom vase') so popular at the Qianlong Court.A virtually identical white jade meiping-form bottle with the same incised four-character mark is in the National Palace Museum, Taipei, and is illustrated in Snuff Bottles in the Collection of the National Palace Museum, Taipei, 1991, no. 125.
The type of mark on this present bottle appears on a series of highly Imperial jades from the Qianlong period, most likely from the latter part, although it may have been used earlier. Although unusual, and only found on Imperial wares of the Qianlong period, this type of clerical script mark is typical of Palace carvings (even if they were commissioned elsewhere, such as Suzhou, although the Court workshops remains the most likely origin). In the Imperial Collection still in Beijing there are pieces which have been in the collection since the eighteenth century which bear precisely this type of mark. See, for instance, a spinach-green jade brushpot illustrated in The Complete Collection of Treasures of the Palace Museum, Jadeware (III), Hong Kong: Commerical Press, 1995, no. 168, and a white jade censer and cover in Zhongguo yuqi quanji, Jade, Vol. 6, Qing dynasty, p. 240, plates 351 and 352. The identical style of writing is also sometimes found on a series of Imperial Qianlong carvings which bear either four- or six-character marks ending in fanggu ('Copying antiquity') instead of the more usual nian zhi ('year made'); see, ibid., no. 153, for a spinach-green jade covered dou; no. 151, for a hero's-vase in a similar colour, although with a diamond-point engraved version of the same style of calligraphy; and no. 147 for a white jade vase with chi-dragon decoration.
Apart from the dated pieces, there is also the evidence of the very deep foot which occurs on jade bowls after 1757, which suggest production from the second half of the reign. This unusual, distinctive and very crisply carved, deep footrim seems to derive from a bowl presented to the Emperor from Turkestan in 1757. For at least two decades thereafter, a series of such deep-footed bowls appears to have been made. See, for instance, ibid., p. 32, plates 51 and 52, a spinach-green jade bowl with an Imperial inscription dated to 1758 and bearing the mark Qianlong yuyong ('for Impieral use of the Qianlong Emperor'); p. 33, plate 53, an inscribed white jade bowl with a poem dated to 1775; and p. 34, plates 54 and 55, another greenish-white jade inscribed bowl, bearing a Qianlong yuyong mark.