Mithridate…AMAZING! I too fall in your camp of thought, it was certainly a cross of some kind. You are 100% correct that the landraces in Jamaica were notoriously different, in fact they were vastly different even by landrace standards. It was most likely a chance cross with a different continent strain and was thankfully recognized for its extreme potency, look, smell, and taste.
This wasn’t something that was being slung around the Boston area, it was so desired that the only way to obtain it was to seek it out and do a lot of begging…even to obtain an 1/8.
You nailed the description of how impossible it was to break apart, it was some of the stickiest bud that ever circulated. Your description on very dark brown is dead on too, I said it was almost black because of just how dark it was but I’m very comfortable saying very dark brown too…nontheless, very dark!
Thank you very much for sharing your insight!