Keeping your Island Sanctuary in Final Fantasy XIV efficient can be rewarding, if not time-consuming. After unlocking this island and upgrading it, you're set to start making some good gil from its amenities through Handicrafts. Making sure you're always stocked up on the needed materials is a must to ensure your mammets can keep doing their jobs.
Island Rock Salt is a material you may overlook while stocking up on materials since food-based handicrafts are the only things that require it. However, these handicrafts come up as recommendations quite frequently, so learning where to get the materials needed to add the right nodes to your gathering routine is a good idea.
How to Get Island Rock Salt in FFXIV's Island Sanctuary
When you set out to fill your pockets with Island Rock Salt, you'll first need to enable the "Gathering" mode on your island. Without this mode active, you won't be able to see or interact with the nodes to get materials. The node you're after if you want Island Rock Salt is the Crystal-banded Rock. You will also need to make sure you have access to the Islekeep's Stone Hammer to extract salt from these nodes.

There are two locations where you can find these nodes. Both of these spots are inside of a small cave, so be careful not to overlook them:
Coral Sands: This small cave holds six Crystal-banded Rock nodes. Some other nodes are nearby, but unfortunately, your gathering route will have to be larger than ideal. You must find five other nodes to hit before returning to this cave since Island Sanctuary gathering nodes respawn after 10 others are gathered.
Screengrab by Fanbyte via Square Enix Pirate Bay: The cave to the east of Pirate Bay only holds four Crystal-banded Rock nodes, and much like the previous cave, your gathering route will have to make a pretty wide circle to find the other seven you need to hit to start respawning these nodes.
Screengrab by Fanbyte via Square Enix