Redstone Ore

"You'll most often find redstone deep below the surface, in the bottom 16 layers of the map. Normally it spawns in large veins of 4-8 blocks, each of which will drop 4-5 redstone and some experience when you mine it with an iron or better pickaxe. You'll get more with a fortune-enchanted pick, of course."

- Duncan Geere

Redstone ore is the ore block from which redstone is obtained.

Mineral veins
Redstone ore can generate in the Overworld in the form of mineral veins. Redstone ore attempts to generate 8 times per chunk in veins of size 8, from altitudes 0 to 16, in all biomes.

Obtaining
The redstone ore block itself (rather than its redstone drops) can be obtained by mining it with an iron or diamond pickaxe with the Silk Touch enchantment.

Usage
Redstone ore drops 4 to 5 redstone and 1–5 experience when mined with an iron pickaxe or better. Mining with a Fortune enchanted pickaxe will increase yields.

Light
Redstone ore will produce light (strength 9) and red particles when clicked, updated, or contacted by any mob (exceptions being a sneaking player and armor stands). This effect will continue until the redstone ore block receives a block tick (averaging 68.27 seconds). This effect does not actually produce redstone power, but the block changes can be detected with an observer or a block update detector.

Subsequent clickings on a redstone ore block will cause it to emit an extra burst of particles per click.

Smelting ingredient
This recipe awards 0.7 experience.

Trivia

 * In the Bedrock Edition, stepping on redstone ore does not cause a block update.