Neat. It looks to me like what is generically known as ‘Chrysanthemum Stone’, which covers a multitude of rock types, although formed in essentially the same way. They’re usually Permian-age rocks within which high temperature and pressure causes them to have flower or star shaped white crystalline deposits that are usually andalusite but can also be celestite, calcite or feldspar. The matrix is often black limestone with high amounts of organic carbon but can also be dolomite, gypsum clay, or porphyry among others.
Sometimes there’s a spectacular isolated deposit (as in this specimen from my collection), and sometimes multiple smaller deposits like scattered snowflakes:
View attachment 2166251
Some more examples at ‘mindat’ link below, but mineral sites tend only to have pictures of ‘display quality’ specimens. With some more extensive Googling, you may find specimens that more resemble yours.
https://www.mindat.org/gm/8275
That’s my best guess.