I also want to add that if doing the 'pearl circuit' isn't your thing, there are 3 plants that drop pearls and golden pearls occasionally. The crowns plants (also dropped from some mobs) are Silver Trumpet Vine (I have gotten about a 50% rate of golden pearl drop at elder), and Maelstrom Snap Dragon, which drops them sometimes at regular harvest (drops sandstone, sunstone and aether as well). If you haven't been lucky enough to get seeds for those, you can grow Fickle Pickle. They drop anything and everything and I have gotten pearls as well as sunstone and aether from them. The pearl circuit is definitely a faster way to get them, but there is much less competition in your garden. :-)
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