These three tumblers were thrown in July 2018 using 400 gr of Staffordshire clay. Half of the clay was wedged with cobalt oxide in the proportion of 2%. The off-white clay was then combined with the blue one by wedging them slightly together.
The aspect of the agate clay doesn’t appear during the throwing as the process leaves a layer of grey slurry on top. The pieces need to be fully trimmed inside and outside to remove the slurry. It’s quite a fastidious process involving scraping the surface with a metal kidney in all directions.
The colour contrast is reinforced by the firing at 1,220o Celsius when the cobalt oxide turns into a strong blue. The tumblers were decorated with a transparent glaze.
Diameter 10 cm. High 8cm.