They appear if you search for ‘selenite geode’ on various nameless shopping channels or search engines.
Now, it is possible to find genuine geodes containing gypsum selenite. They are quite rare, and almost always colourless.
These geodes, however.. Well, they’re dyed Moroccan geodes, and I have no idea where they’ve pulled selenite from.
Update 04/07/2020 – I have bought one of these geodes and added photos.
It’s probably an attempt to capitalise on the popularity of selenite with the new age and reiki community. Every one of these listings I saw mentioned ‘fertility’.
As a general rule, look carefully at any geode with a black coating. It’s normally paint (In amethyst and heat treated amethyst-citrine, this is due to the fragile shell of the geodes being coated in concrete for strength).
In this case, they have likely been painted to cover up the bright pink or purple dye patches on the outside – see photos below.
It is worth noting that an extremely bright colour in itself is not diagnostic of a fake, one only needs to look at gemmy rhodonite, or natural chalcanthite to see that. Experience will give you an idea from a glance which colours don’t look ‘right’, but everyone is wrong sometimes.
If you have anything similar, a very easy test will be to dab a bit of Acetone or another solvent (nail polish remover, white spirits) onto a tissue and wipe it on the suspiciously coloured crystals.
In all likelihood pink or purple dye would come straight off these onto the tissue.
You’re welcome to share this information or post with any contacts or groups you know of that it may be of interest to. I’ll try and find another for next week.