Hardened Glass

Hardened Glass is made in the Induction Smelter using 2 Pulverized Obsidian  and either 1 Lead Ingot or 1 Pulverized Lead, which yields 2 Hardened Glass.

This glass has an extremely high blast resistance and cannot be broken by any explosive weaker than a Nuke. 2 layers of this glass will resist any explosion in the game, including a full Nuclear Reactor.

It is used to craft several of the Thermal expansion items, such as the Tesseract, Redstone Energy Cell, Liquiducts, and Redstone Energy Conduits.

To remove placed hardened glass, use any BuildCraft compatible Wrench (or the OmniWrench) and shift right click it. The glass will drop on the ground as an item. Note that this is the only way to retrieve placed glass.