You don't need any Eldarium to craft Stormglass pieces (even if they look similar in texture to Eldarium-infused decorations). You can build a base out of Stormglass pieces without worrying about running into Vaults. Stormglass is a Tier 3 building material, but every kind of Tier 3 building piece in the base game, DLCs, in-game store (Bazaar), or Battle Pass require the same materials as Stormglass to get crafted since Tier 3 pieces only vary in aspect, so consider the Stormglass building set as a different "skin" from the Reinforced Stone set that belongs to the base game. You can craft Stormglass building pieces and any other Tier 3 pieces (except awnings) with the same materials - Hardened Bricks, Steel Reinforcements, and Shaped Wood. The awning pieces from each Tier 3 building set usually require Iron Reinforcements, Wood, and Shaped Wood instead (Black Ice pieces also need these materials together with Black Ice, though).