why would you want to is an excellent question. i know how to trap a spirit in the grave, but not a crystal. it would be neat to add one to my BoS but i don't know why anyone would want to do that.
perhaps you could trap a very weak spirit, but i wouldn't exactly know how. if there's a way to get it to go inside then quickly do a binding spell on the crystal, but i'm not sure.
i'm still a little stunned someone would want to trap a spirit. if you want it to help you, you can just ask. spirits are all around us, they aren't exclusive to old weather torn buildings. they wander the earth and when they find a place or person they like, they'll stay. if you come across a spirit attached to an object, it's bound to the object, so you could use that, but i DO NOT suggest doing that. on one hand it's horrible, because you're blackmailing the spirit, second, those spirits tend to be strong. if you take their ring for example, they'll get it back by going through you.
A captured ghost won't be any more scientifically provable than a free-range ghost, so you may find your attempt to use this as proof to be a bit lacking.
And while I commend your intention to capture haunts people don't want around, you should be forewarned that you'll no doubt encounter non-ghostly haunts which can be far more dangerous and very hard to distinguish from a malicious ghostly presence... and there are totally reasons why priests get extensive training in how to handle such things.
Don't let this discourage you though - if you really want to do this then that's awesome! You just need to be prepared to eventually face something worse than annoying dead person.
so like Ghostbusters? i'm afraid that's a hard test, proving they are real to those who strongly don't believe. faith is a powerful thing, and it's hard to disprove that as well. good luck to you, just be prepaid for a difficult journey. personally, i'd let it be, someone doesn't believe something you know is real, no one's getting hurt, so ignore it. i just hope you don't end up harming [or getting hurt] a spirit to prove you're right.
Why would you want to trap a soul in a crystal?
Are you playing a lot of Skyrim?
no,I don't know of any such spell,nor do I wish to know.According to me such a spell would be too dangerous to perform.And you can simply use a spell to create bond.You don't need draw a soul close to be close to someone.
no not like Ghost-busters we would go to a haunted location we would stay for a weekend first day we would go to the haunted location and do a walk-through it will be life footage not recorded there will only be two of us and only two cameras that run on are energy second day we will make the ghost angry we will have Protection we will tell it to leave and if it dose not the next day we will capture the ghost. we will practice for a time before doing this.