Refractor

Amethyst can be used with redstone lamps and levers to make a machine that has two variants

First things first, the charger, which recharges the redstone mechanics. Made with an item frame in the top-mid, gold blocks in the four corners, redstone lamps in the three other sides, and a redstone block in the middle. Once powered by using redstone, it opens. you put your redstone item into it, and after a bit it recharges the durability.

1: Scatterer: This Item shoots a burst of light, doing 4x10-15 dmg. It goes 5 blocks before fizzling out. It uses up durability equaling the amount of beams it shot. It can be repaired by putting it in a charger for 1000-2000 ticks. Lasts about 100 beams.

2: Focuser: Shoots one beam doing 20 damage and taking up 5 durability. Goes 20 blocks before fizzling out. Can be repaired by putting it into charger for 1000-1500 ticks. Lasts about 15 shots.

There is a 5% chance that the amethyst will shatter in the item, forcing you to make a new lens (amethyst in middle, gold in clock formation. Makes 1) and put it into the item, by holding it in your off-hand and sneaking with the item in your main hand. Every use the item doesn't break on, the chance of breaking increases. 

These would be used as end-game ranged weapons.