Icy basalt is an item that can be used to teleport to Weiss, near the herb patches. Using it to teleport consumes the icy basalt. It may only be used after finishing Making Friends with My Arm.
This teleport can be incorporated into a portal within a Portal Chamber using 100 times the required resources (300 efh salt, 100 te salt, and 100 basalt), or in a Portal Nexus using 1,000 times the required resources (3000 efh salt, 1000 te salt, and 1000 basalt).
Attempting to use the item whilst standing at the teleport destination will result in a game message stating You are already here. You don't want to burn to ashes then reconstitute, just to travel to the same place do you?