Continued System for the Destruction of Dropped Items

When any dropped item touches lava, it is destroyed. What would make a slight difference to the game, but a huge difference to farms and item sorting, is a renewed system for the interactions between dropped items and fire. My idea is that when a dropped item comes in contact with fire, it is up to a variable whether the item remains or is destroyed. This variable is based on if that item would be considered fireproof. For example, wood items and nature items would be destroyed by the fire, while metals and stone like iron, gold, andesite, diamond, obsidian, etc. , would remain intact when in contact with fire while in dropped item form. This would make item sorting much easier, and actually came to mind when I was thinking about how to sort out the roses in an iron farm.