Nether Quartz

Nether quartz is a Nether exclusive item obtained by mining nether quartz ore. Nether quartz can be obtained in the Pocket Edition when it is spawned by a Nether Reactor, although in the Pocket Edition its only use is to craft smooth quartz blocks.

Smelting
Note that the nether quartz ore block cannot be obtained without the Silk Touch enchantment, and that this smelting is slightly inefficient because, with Fortune, you can get more than one quartz per ore. Also, there would be no reason to collect it with silk touch if you were just going to smelt it as it would be more efficient on long excursions to save space and to gather the experience earned from mining the quartz ore for later. In addition, you could place the ore and destroy it with a pickaxe to get the same yield.

Trivia

 * Nether quartz ore appears to be quite common, but in reality, is about as common as iron ore in the Overworld, each spawning approximately 70 ores per chunk, although it spawns in large veins similar to coal ore. It seems more common because it can spawn on almost any layer within the Nether (except the extreme upper or lower layers), the Nether has more exposed blocks than an Overworld cave, and Netherrack can be removed far more quickly than stone.


 * If the player entered the Nether before 1.5 was released, then after the update was released, nether quartz ore would only spawn in newly generated chunks. This makes it difficult to find nether quartz in old worlds.


 * Although in real life striking a quartz crystal on a piece of steel is just as effective as flint on steel (for making sparks), there seems to be no plan to implement a quartz and steel striker, possibly because gravel (thus, flint) is more common than nether quartz, so it is cheaper to use flint anyway.