Siofra shared some fantastic links- the only other thing that came to mind that may help is @Eliza_01’s work with a Black Obsidian Disk used for obsidian gazing.
While not the same as a black mirror, it does seem like the black obsidian disk has some similiarites and can both be used for scrying. Just sharing it here in case it helps/sparks some inspiration for using your black mirror!
Congrats on your lovely new tool, @Amaris_Bane- happy scrying!
