Crystals, in the glaze on a pot, can be traced back to China in the 10th century. Its not certain whether these were intentional or not. The history as we know them dates back to the 19th century. It was never a secret that if a glaze mix contained a good percentage of Zinc oxide then crystals would develop. Their presence were sometimes considered a mistake or accident and advice was given on how to avoid these ‘blemishes’ on pottery ware.
The highly decorative ware of the mid 19th century gave way to the more graceful and simplistic decorative style of the Art Nouveau era. Glazes were appreciated more in their own right and this opened the door to crystal development. Chemists and potters working in France, Austria and Germany were experimenting with crystal glazes leading up to the 20th century and among the first companies in England to experiment was the Royal Doulton Company and Pilkington’s.
Doulton’s were leading the field producing large and beautiful crystals right up to the outbreak of war in 1914 when production stopped as ‘producing crystal glazes was too expensive and unpredictable’. So, nothing has changed there!
Today there are numbers of potters working in all parts of the world developing crystal glazed ware as an art form as we are trying to do.