Nether Quartz

Nether quartz, or simply quartz, is a smooth, white mineral found in the Nether.

Mining
Nether quartz ore mined using a pickaxe drops one unit of nether quartz. If the pickaxe is enchanted with Fortune, it may drop an extra unit per level of Fortune, up to a maximum of four with Fortune III. If the pickaxe is enchanted with Silk Touch, the ore drops itself.

Trading
Expert-level stone mason villagers have a $2/3$ chance to trade 12 nether quartz for one emerald $$, and this trade is always offered $$.

Trivia

 * All of the sensor related items that are craftable (comparator, daylight sensor, observer) are crafted with some nether quartz involved.