Minecraft wiki entry for Amethyst_farming, associated text: First you will need to build 1 floor, but make sure that it is at least 5 blocks over the highest block of amethyst. Then you will need to make a hole in the floor where a block of budding amethyst is directly below it and repeat that until directly above every block of budding amethyst there is a hole. You can now place a water bucket in each hole. This will allow you to access the budding amethyst without blocking any over it, so that the collection system can pick it up. Now you will need to build the collection system itself on the bottom floor which is under the blocks of amethyst (you will have needed to dug out the area first). You can do the system however you want, with water flowing for example, which pushes the amethyst shards over a hopper minecart system which collects it and funnels it into a chest. The last step is to light up the area. To use the farm you need to wait for the amethyst to grow, and to harvest you need to swim down each hole and harvest all the amethyst there. If you drop any amethyst it will be collected, so despawning is not a problem.