Glowstone
From Timebomb Madness Wiki
"Emits light."
Overview
Glowstone is a block debuted in the base game. It costs 100P to buy 2 of them. It has 15HP. It's used to illuminate surfaces. The maximum amount of glowstone is 6 blocks. In version 1.6B the lighting was entirely reworked to look much nicer, but did come with minor performance issues.
