Snapshot 21w14a includes three new raw metals: raw iron, raw copper, and raw gold.
Each of these three raw metals drops from their respective ore block. In previous versions of the game, the ores dropped only themselves.
Raw metals act no different to their respective ores, apart from the fact they can't be placed down. Raw metals still must be refined by being smelted down into ingots, for use in crafting recipes.
The reason these items have been added is to syncronise the collection of all ores, making it so all ores in the game now drop items.
This change allows all ores to be effected by the Fortune enchantment, which allows you to gain extra minerals from a single ore block.
To get an ore block to drop itself instead of a raw metal item now, the Silk Touch enchantment must be used on the tool you are using.
Other changes in this snapshot include oxidized copper now being able to be waxed and several bugs being fixed.
The Caves & Cliffs update is set to release for all active editions in just a few months, and some of its major features are still awaiting addition.
For a visual guide to the changes in this snapshot, watch the video below: