Here are two small seal materials I purchased from a calligraphy supply store about 20 years ago. They are Barin stone seal materials, which have a slightly transparent appearance like water yokan (a type of jelly). There are two pieces, one light brown and one gray. The brown one is 1.2 x 1.2 cm, and the gray one is slightly smaller. Both are 4 cm tall. They are housed in a carefully crafted box lined with fabric. How about using them to create a refined seal for kana calligraphy works?