Redstone Ore

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

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

Redstone ore veins form at the bottom 16 layers of the map. Below layer 14, it can be found in 1.025% of stone. There are an average of about 24.8 redstone ores per chunk.

Redstone ore forms in veins made up of 4 to 8 blocks. However, multiple veins together or non-stone surrounding the vein can change those numbers.

Usage
Redstone ore drops 4 to 5 redstone when mined with an iron pickaxe or better.

Redstone ore will produce light (strength 9) and red particles when clicked, updated, or contacted by any mob (including the player, if not sneaking). This effect will continue until the redstone ore block receives a block tick (averaging 47 seconds). This effect does not actually produce redstone power, but the block changes can be detected with a block update detector allowing redstone ore to act like a pressure plate for mobs, but capable of detecting contact with its sides and bottom surfaces as well.

As a smelting ingredient
Smelting the ore instead of mining it is highly inefficient, as mining the ore block yields 4 to 5 redstone rather than the single redstone that smelting yields.

Trivia

 * When added to the game, all redstone-related blocks had no official name. In Alpha 1.0.4, July 9, 2010, the name Redstone was given by Notch after demands from the community.
 * Coal is more common as an ore when mining, but technically, redstone is more plentiful since when deep enough, the ore is 1.5x more common than iron, and yields 4-5 redstone dust for every ore.
 * Like most ores, redstone ore is fairly evenly distributed horizontally. It is not more common near lava pools but may appear more common near deep lava pools because more blocks are pre-exposed by the world generator boring out the cave.
 * Redstone ore can be found in Pocket Edition and can be mined but the dust has no use yet except for making clocks, compasses, and powered rails.
 * Redstone, coal, lapis lazuli, diamond, Nether quartz, and emerald ores are the ores that require a silk touch tool to obtain the ore block in survival.
 * Redstone is the only ore found in the overworld that does not exist in real life.
 * One redstone-like material in real life is called iron oxide (rust), a red looking stone/dust with very small conductive properties, almost like redstone which conducts up to only 15 blocks.
 * However, copper is more realistic, as copper conducts electricity as well.
 * In Minecraft Pocket Edition, stepping on redstone ore does not cause a block update.