Mantianxing is a collector name, commonly translated as “stars across the sky.” Sellers may use it for a Lion Head–associated market form with many small, dense texture points, but usage is not controlled and can vary between regions, growers, and marketplaces.
The name is useful for describing an appearance. It does not by itself prove botanical species, a particular tree, geographic origin, age, rarity, or value. Before buying, compare the actual outline, bases, ridge pattern, measurements, condition, and treatment disclosure instead of accepting the label as authentication.
Ask for neutral-light photographs from the front, side, top, and base with both walnuts in the same frame. If a seller connects the pair to a specific tree or origin, request documented provenance and treat anything that cannot be checked as unknown.