High-Quality Duanxi Inkstone (in wooden box)

Purchased over 50 years ago at a calligraphy specialty store in Nanjing Road, China, by my father for my mother (a calligrapher). The wooden box is also meticulously crafted.
The inkstone was chosen for its refined face and exquisite carving.
While the specific type, such as Laokeng, Mazikeng, Rongkeng, or Kengziyan, is unknown, it was certified as a Duanxi Inkstone by the owner of a long-established calligraphy specialty store in Japan. My father certainly had a discerning eye for high-quality items, so I believe it was quite expensive. However, as it has been stored in my study, I am currently unable to provide details of the purchase price. Please be aware of this.
It is unused.
It has been washed.

*I myself have been practicing calligraphy for 40 years, but I am decluttering as I have many inkstones.
The last two photos show the inkstone wet with water. I took them by the window, but the distinct patterns did not come out well in the photos. When wet, brown and deep purple hues emerge in places.
Weight: 1550g.

Incidentally, many of my inkstones are Duanxi from my mother. I also use and favor Mazikeng, Nakamura Inkstone from Kochi, Japan, Ubatake, and Ryukei depending on the artwork.

*I am currently organizing my study. If you are interested, I would appreciate your consideration. I also plan to list a Nachiguro (made by Kōhō) soon.

*No claims or returns, please.