Sandstone and Sunstone can be found on bosses in Chantel and trial of spheres. You can also transmute stone to sandstone and then sandstone to sunstone. Another way to get sunstone and sandstone is to garden. There are several plants that gives those as rewards. I may have gotten a few from Maelstrom Snapdragons. I think there are a few more but I can't remember what they are.
Golden Pearls are from pearls. The best place to find those is the Lunarium. There are several spawn points with in the portico area. On each 'run' you can find at least 2 spawns. You can then transmute the pearls to golden pearls. Another way to get pearls is through gardening. I have gotten quite a few as rewards from Maelstrom Snapdragons.