Astral Sorcery's Transmutation works by linking Floating Crystals to e.g. Iron Ore Blocks (they get converted to Starmetal Ore Blocks).
Floating Crystals can either be found in the world (since this is Skyblock this is not possible) or be crafted.

Problem is: Their crafting recipe depends on Starmetal, which can only be obtained by Transmutation.

Recipe for the Floating Crystal:

Possible solutions:

• Add an alternative/simpler crafting recipe for Floating Crystals. (May not be that easy because crystals have "metadata", i.e. size, purity & cutting.)
• Add an alternative crafting recipe for Starmetal.

Here's how other Skyblock modpacks solve this:

Sky Factory 4 / "Core":

Awakening - Sky of Diamonds (quest book):

Maybe a smeltery alloy Recipe? 144mB Molten Iron + 1000mB Liquid Starlight = 144mB Molten Starmetal

Or casting 1000mB Liquid Starlight on an Iron Ingot to create an Starmetal Ingot.

How would you get a smeltery?
For "Grout" you will need clay, and I think the only way to get clay is through the transmutation process (that would be another circular dependency). Or am I missing something?

Totally missed that. I think the smeltery should be a litle bit easier to get.
Depending it on late game astral sorcery seems not beneficial to me, especially as it is required to get iron tools.

A Floating Crystal is placed in the map and transmutation can be done that way.