Just dug something up regarding Benzene and crystal structure which might explain the strange formations your getting:
modes by which the molecules stack into crystals!
Pi stacking, yes! Aromatic moieties are actually electromagnetic, with the center being more positive and the ring being more negative. The field around a benzene ring is actually a toroidal magnetic field, due to the synchronization of electron spin states… so as long as the rest of the bulky chiral cannabinoid molecule is bent, twisted, or otherwise not too sterically hindered in the regions around the aromaticity, the molecules can interact mainly by attractive van der Waals forces.
Aiding their abilities to crystallize are their much higher stability (lower overall potential energy) than that of the other Δ#-THC isomers, due to their extended pi orbital conjugation.
In the case of CBN, molecules may stack closely offset at the conjugated ring structures, similar to biphenyl, which is actually a more stable conformation than the flat, directly fused double benzene molecule, naphthalene (mothballs).
In the case of the Δ10 & Δ10a-THC isomers, molecules likely stack as lamellae perpendicular to one another in alternating
[…ethene-benzene•benzene-ethene•ethene-benzene•benzene-ethene…]
orientation, similar to styrene crystals.
Bottom line is intermolecular forces and molecule mass are big influences on crystal structure and crystallizion behavior:
-COOH, -OH, and pi stacking are some top contributors. Also, making a compound more rigid and with less conformations can help, too.
All pulled from here:
Why won’t D9/D8 THC Crystallize? - Hash and Stuff / Crystallization - Future4200