New Nether crystal: Kyanite

Kyanite crystals are found in the Nether, near lava seas. They can be mined to obtain Kyanite Shards. 

Kyanite clusters

These are big crystals, found near lava seas. They are made of many little clusters, like pointed dripstone does, but in all directions. Breaking it gives 2 Kyanite shards.

Temperature sensor

Crafted with 3 Kyanite shards, 3 cobblestone and 3 glass. Emits a redstone signal in base of the temperature detected. Higher temperature means stronger signal. Can also detect what fuel a furnace used. 

Crystal panel 

Crafted with 6 Kyanite shards. It's a transparent blue block, that acts also as a termic isolator. Can be used to make bottles. If there is a Crystal panel between a heat source and a temperature sensor, the sensor won't be able to detect that heat source, like we isolate Skulk Sensors with wool

Cooling rod

Crafted with 2 Kyanite crystals and 1 Copper ingot. When powered by redstone, cools a 5x5 area. This interferes with the Temperature sensors, making them detect a lower temperature, slow down furnaces, making them use more fuel, and can also give the freezing effect if close enough

Glowing Rod

Crafted with 1 Kyanite shard, 1 Amethyst shard and 1 Iron ingot. Emits a blue light. Can be placed underwater

Kyanite block

Crafted with 4 Kyanite shards. A decorative block