With Silk Touch enchantment obtained, you can also mine entire diamond or coal ores instead of only getting their drops. This enchantment can also be used to gather items that are quite fragile and prone to breakings, such as ice or glass. Instead of getting the dropped items, using Silk Touch allows you to mine the entire block itself. The Silk Touch is an enchantment in Minecraft that helps you mine blocks that are usually unobtainable with standard mining.

Blocks Obtainable With Silk Touch in Minecraft.