Page 284 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

Remarkably this pigment was only identified by modern science as a "new" and interesting sili­
cate in 1989 (Finger, Hazen, and Hemley 1989). 5
Examples of objects from the Han dynasty on which Han purple pigment have been found
include a gilded bronze vessel with painted purple decoration on the inside cover; a bronze ves­
sel; the top of a hsien (steamer) with painted decoration in red, light blue, and light purple; and
many ceramic objects.
PLATE 53 illustrates an octagonal Han purple pigment stick from the collections of the
Ostasiatiska Museet, Stockholm. PLATE 54 shows a mounted preparation of Han purple from
a Chinese painted bronze vessel of the Han dynasty. The pigment is viewed under par­
tially crossed polars, showing glassy particles with pink-purple birefringence (Fitzhugh and
Zycherman 1992).
The Chinese synthesis of an artificial inorganic purple pigment represents a unique
achievement: the only other purples of antiquity were obtained from organic colorants; reddish
purple pigments were obtained from iron oxide earth, where available.
Analysis of a white coating on two octagonal pigment sticks of Han purple surprisingly
identified the coating as cerrusite, PbC0 3 , and a mixture of two different lead phosphates,
Pb 5 (P0 4 ) 3 OH and Pb 9 (P0 4 ) 6 , which are associated with the sticks' manufacture. Lead oxide
was used as a flux in the preparation of these pigments. Brill, Tong, and Dohrenwend (1991) syn­
thesized Han purple using several mixtures, including barium chloride, BaCl 2 , copper carbon­
ate, CuC0 3 , silica, Si0 2 , and a synthetic natron flux (a mixture of sodium sesquicarbonate,
Na 2 C0 3 NaHC0 3 , sodium sulfate, Na 2 SO 4 -10H 2 O, and sodium chloride, NaCl), which were
heated between 870 °C and 1000 °C.

Notes
1 A most remarkable property was claimed for be better matches to the experimentally deter­
chrysocolla, according to Sir Richard Burton's mined data for entries given as "superceded"
1886 translation of The Perfumed Garden in the more recently revised editions.
ofShaykh Nefzawi, an Arabic text written by 3 One of the difficulties in modern replication work
Shaykh Umar ibn Muhammed al-Nefzawi in the is that these blue colors are stable only in very
fourteenth to fifteenth century: "[Pjrocure for alkaline glazes, which tend to have high thermal
yourself extraordinary erections by eating of coefficients of expansion so that they can be used
chrysocolla the size of a mustard grain. The only with ceramics or pastes with a high quartz
excitement resulting from the use of this nostrum content, which are not used, in any practical
is unparalleled and all your qualifications for sense, today.
coitus will be increased" (Burton [i886 ] 1974, 4 Vitruvius De architectura 7.11 (Vitruvius I93i) .
ch. 13). This aphrodisiac effect is most improb­ 5 The chemists did not realize that the "novel"
able; any such effect must surely have been in compound they had made had already been syn­
the mind rather than in the chrysocolla. thesized, in fact, by Chinese alchemists many
2 The I C D D periodically issues revisions to the centuries earlier and was therefore not new to
X-ray defraction data, which in most instances ' science, as they had thought.
improves the quality of information available. For
some more variable minerals such as chrysocolla,
however, some of the earlier I C D D file entries may

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