I don’t see Pelt lines in first picture (blue galaxy). Marble looks new in the pictures and who would buff a blue galaxy? My guesses would be Akro patch, Ppp or Jabo. My suggestion is for some real answers post another 8-10 pictures of the marble with back light to verify base color. Anxious to be proven wrong and congratulate you on VERY hard to find marble.
Sorry to hear about your health issues. Get well soon. We use display cases you can buy at Hobby Lobby and then use sound proof foam purchased on Amazon.