First, test it using a reagent. Ehrlich's reagent can be bought online as 'LSD test solution' or reagent or keywords like that.
People are very unlikely to acquire crystal LSD while at the same time to not know what to do with it. It is rare and usually requires monetary investment and a certain type of connection. If one gets involved with that, typically there is great intention of doing something with the LSD and knowhow that comes with it.
So, unfortunately the chances (statistics are not personal and they don't lie) are that it is not LSD but a cheaper compound like a DOX or NBOMe. We shouldn't debate about trustworthiness of what you are saying or "someone you know", unless you have already verified it actually being LSD through actual analysis. Just be sure, nobody's word should be worth that kind of risk.
So, after doing that we might discussing what to do with it. We are not here to really instruct you on manufacture and distribution of drugs, but harm reduction related warnings are in order like: better to not attempt making blotter as it is very challenging and requires advanced material / methods, it may seem relatively simple and doable but it should be left to experienced people.
Wear gloves. Have a very precise analytical laboratory scale. IMO stick to liquid LSD, by putting it in something like everclear or quality vodka. The maths should be simple.
But start with the test!!!