This set of rocks was purchased for my brother around 1957 when he lived in LA. My understanding is that it is from a shop in Disneyland called "Jemrocks Assay Office". I have included 3 pictures of the set, including one showing a sticker on the box with "Disneyland", "Jemrocks", & "c Walt Disney Productions".
If anyone has any information on this set as well as possible value, I would sure appreciate it. Thanks!