It will have to be dissolved in alcohol or DCM (yuck, strong garlic smell!!) or something else to allow enough of the Salvinorin to cross through the skin and into the blood fast enough for it to be effective at all.  Just putting crystals in your mouth does not do the trick.   Remember an effective Quid is 20 to 30 large leaves at least, chewed & mushed around in the mouth for like 30 to 60 minutes, and that is if your using fresh leaf!!   That means a whole lot of pure Salvinorin crystals to do anything at all by them self. 

hint: the oils in the leaf, help aid in absorption though the mucus membrane of the mouth.

Once again, a dose of pure Salvinorin is smaller than a single grain of salt.  A drop of acetone would more than likely hold a whole lot more than would be necessary for 15 people!!!

Best to make yourself a tincture, or even better, (also easier) dissolve it in acetone and soak some plain leaf in it & let it dry completely, to "enhance" the leaf.  Kind of like making your own extract

Seriously, there have been nothing but horribly terrifying reports concerning pure Salvinorin crystals!!!  like  benzyme said, unless you have access to a scale that can accurately weight down to 0.00001g, you really shouldn't even consider it!!!

When I say a dose is smaller than a single grain of salt, that is not an exaggeration, that is for real!!

Here is a quote from Sieberts site, sagewisdom.org:

and here is a link to his report of accidentally ODing on pure Salvinorin:

Daniel Seberts report

Daniel is (or at least used to be) the guru of Salvia Divinorum!!  His research is why most of us have even heard of Salvia.  I'd take his word on it!!

WS