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Ho many do you have and what are the sizes?
Can you send a photo that shows all of them in a grouping and you mention "They open up with a very small intention" is there a written note inside each?
From the images; the glaze surface and form indicates that these are hand made pieces that were done in an art pottery studio or class setting. The glaze is a type of thick modern Asian raku style dating this to the mid to late 20th century. They are decorative and lidded so as little mementos. As unsigned studio art pottery pieces they could have been made various places such as Japan, China or America. A fair asking price is $5 - $15 each.
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