Pottery In Australia Vol 38 No 3 September 1999

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Kissed by Fire
Crystalline glazes have been around for a long time with the first ones appearing in China as oil-spot
glazes in the Sung Dynasty (AD 960-1279). The earliest specific studies in zinc crystals were
conducted in France during the 1850s. Article by PETER WILSON
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Crystalline glazes have been around for a long time
with the first ones appearing in China as oil-spot
glazes in the Sung Dynasty (AD 960-1279). Later
they appeared in Chinese porcelains in the late Ming
Dynasty around 1650. They then re-appeared in
connection with the Art Nouveau movement in the late
nineteenth century as an attempt to reproduce antique
Chinese porcelains.
The earliest specific studies in zinc crystals were
conducted in France during the 1850s. The ceramic
chemists working in the factories of the National
Porcelain Factory in Sevres well understood that glazes
with an excess of zinc silicate and titanium would
produce crystals. They wrote papers and disseminated
their findings, warning others of these glaze defects. It is
ironic that what was considered then to be a defect, has
been now been developed into a highly technical artf orm
in itself.
Despite the warnings, experimentation continued and
the development of crystalline glazes happened
throughout Europe. In the National Porcelain Facto1y at
Sevres, whole ranges of wares were designed and made
specifically for crystalline glazes. Similar developments
occurred in Denmark, Germany and the US.
It is in the United States that Adelaide Alsop Robineau
made her significant contribution to the study of
crystalline glazes and is largely responsible for bringing
Crystal glazed bowls.
Left: w40 x 36cm; Above w48 x h38cm
them into the independent potter's studio. She began her
work with crystals in 1904, documenting her extensive
research until her death in 1929. From then until the
1970s, there was little or no additional work in the area.
Since then there has been a growing interest in crystalline
glazes, especially in the US and Britain, where there are
many devotees and collectors of crystal glazed pots.
There are however, just as many detractors.
I dislike large, flowery crystal-glazed pots. They are
garish and ostentatious. My own interest in this topic
began quite by accident whilst exploring the effects of
zinc in glazes and I was surprised with the diversity of
results attainable just by extending the soaking period
during the firings. I am more concerned about the
development of a softer surface which comprises
elements of prima1y and secondary crystals, haloes and
interesting colour formation. To this end, the addition of
between five and ten parts of magnesium silicate creates
interesting effects. There is a sense of unpredictability
and uniqueness about these glazes which is very exciting
- a pot kissed by the fire!
A unique glaze however, does not in itself ensure
aesthetic significance, and mastering crystalline glazes is
only one aspect of the equation, the difficulty lies in
finding some sort of aesthetic balance. Daniel Rhodes
says in his book, Clay and Glazes for the Potter, ' ... the
presence of spectacular crystals on the sides of pots,
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24 POTTERY IN AUSTRALIA+ 38/3 SEPTEMBER 1999