This bowl is 17 cm in diameter, and 7,5 cm high, and made from an orange fired stoneware. The body is covered with a thich glaze, which stops on the outside at twothirds of the bowl. The glaze ranges from an almost black at the rim to and almost white, showing gorgeous blue tinges. This bowl was part of the Stolk collection, and bought by this collector at Stödel and Goudsmit in 1975. I bought the bowl at Peerdeman auctions, who sold part of the Stolk collection.
A bowl with a very similar glaze is at the Halwill Museum.
Goran Schmidt Armory (CC BY-SA) http://emuseumplus.lsh.se/eMuseumPlus?service=ExternalInterface&module=literature&objectId=96225&viewType=detailView