// Definition
An early form of high-purity THCA concentrate produced by extensively purging BHO (butane hash oil) at low temperatures until it transforms into a dry, powdery or rocky consistency.
// From the Episode
A panelist in episode 033 described rock butter as a precursor to modern THCA crystalline products: 'That's what rock butter was. We purged to powder and it was testing 90% THCA.'