Mt. Mortar
you can find it in waterfall cave in kanto
The Silver Cave is located in Mt. Silver in which you can go after you get all the Johto and Kanto badges. In the Silver Cave you can find lots of strong Pokemon and fight the final boss, Red at the top of the cave.
Union Cave
Dark cave.
it's rare to find a moonstone
You find it in Union Cave.
you can not buy a moonstone in any Pokemon game but you can find them somewhere
You can find Mewtwo in the back of Cerulean Cave.
You can find Waterfall in the Dark Cave.
no but you can find one on routes 34, 35, and 37 and in cerulean cave
You get it on Route 27 inside the cave
you find the sihny ston in mewtoo's cave