Glowstone Dust

Glowstone Dust is an item which is used to craft glowstone. It is also used in potion brewing to create thick potions or increase the strength or potency of potions. It can be obtained from mining glowstone (2-4 pieces, more if fortune enchantment is used), killing witches, trading, blazes (Console Edition only) and the Nether Reactor (Pocket Edition only).

From blocks of glowstone
When broken using anything other than a Silk Touch-enchanted tool, a block of glowstone will drop 2–4 glowstone dust. A Fortune enchantment increases the chances of higher drops, but even then, the maximum drop is 4 pieces of glowstone dust.

From witches
A witch may drop up to 6 pieces of glowstone dust upon death.

From trading
Glowstone dust can be acquired through trading.

From blazes (Console Edition only)
In the Console Edition, a Blaze drops 0–2 glowstone dust upon death. This makes glowstone a renewable resource in the Console Editions despite the lack of glowstone clusters due to small worlds.

From the Nether Reactor (Pocket Edition only)
In Pocket Edition, glowstone dust can be obtained by creating and activating the Nether Reactor, which drops enough dust for around usually 15 glowstone blocks. Glowstone blocks can be crafted with the PE crafting table and does not require the stonecutter.

Trivia

 * In the code, Glowstone Dust is referenced as "lightStoneDust" (formerly "yellowdust").
 * The icon for Glowstone Dust is a recolored version of the Redstone icon. Sugar and Gunpowder, while similar in shape, have other changes.
 * It's possible to get glowstone dust without even entering The Nether, as witches can drop it.

Gallery
Glowstonestaub Pierre lumineuse (poudre) Izzókő-por Glowstone Dust 발광석 가루 Gloeisteenstof Jasnopył pt-br:Glowstone (Pó) Светопыль 萤石粉