So, In explorer, you have a chance of encountering a Magpie and its hoard of shiny rocks. This is a very easy way to get shiny rocks. But I don't think they are really rocks, nor are they actually shiny.
throughout some research, I found that magpies do not have a preference for shiny objects. In fact, magpies can easily get scared of shiny objects. But yet, you only get SHINY rocks from the magpie encounter?
Something of this seems a bit off. If you also look closely at one of the shiny rocks, it actually has a plastic gleam look to them. If the rocks, specifically quarts, were polished by humans, would have a glossy or glass shine to them. not to mention the coloration would be a bit bolder and more smooth.
Now, I think that the shiny rocks really are actual plastic. Such as ones used as toys and/or decorations for houses. A large majority of wasted plastic is toys. Toys that are most likely thrown away are ones that do not have a function or are plain-looking. Such as plastic rock toys.
Plastic is not shiny but can have a similar shine to it like a polished rock or gem.