Glowstone

Glowstone

Name	Glowstone
Type	Block
Tool	Any tool
Stackable	Yes (64)
Data Value	89
Source Mod	Vanilla Minecraft

Glowstone is an ore found in the Nether or in Mystcraft Ages written with the Glowstone feature. It is typically found growing from the roof of the Nether in coral-like formations. Glowstone drops 1 to 4 glowstone dust when mined by hand. It can also be mined with a Rock Cutter or another tool with the Silk Touch enchantment to gather the block, which can then be infinitely processed back and forth in a Macerator to turn it to dust and a Compressor to turn it back to blocks without any loss of Glowstone Dust. However, this requires some sort of method of EU generation.

Using a Jetpack or an Electric Jetpack can make the collection process of glowstone easier. Also useful are a Rockcutter/Silk Touch tool for gathering the blocks themselves, a Portal Gun (as portals can be placed on Glowstone itself, despite it being a technically "transparent" block) and some way of defending oneself from Ghast fireballs, as mining Glowstone can leave the player in a position which is very vulnerable to Ghast fire.

For more information, see this item's Minecraft Wiki page.