Fossil crafting +1 spectre

Hi All,

can someone enlighten me, how you can craft +1 spectre on gear?

I have seen some older threads where you can get it on boots, but I only achive +1 spectre gems, not +1spectre.

I have found one sh*tty chest which has the mod "+1 spectre" in delve.

Is there any way to combine fossils to get this mod? I have tried to figure it out on poe.db but I haven´t found that mod.....the possibilities seems endless :D

Which base items you have to use and which fossil combinations?

I have gathered quite some fossils in SSF and want to learn about crafting these,, if it is possible at all?

Or are there other possibilities via essences or alteration spamming?

Thank you for your help.

Cheers,