Best "mdma" I ever had was large brown crystals. Couldnt see through them and they busted into sand, smelled like licorice. Was told that it was the sassiest M a lot of long time rollers (friends and foafs) had ever done. After going through 14gs (with a multitude of friends over the course of a few months) ive done research and found that pure mdma is clear crystals, anything dark brown and sandy (moist) called "sassafrass" is likely Foxy (5 meo dipt). Back in the day when people were buyin pressed pills I heard about foxy pills and how dangerous they were and that some kids had died but this stuff was like pure magic. If that wasnt mdma then I dont wanna do mdma again. "Sass" or Foxy is a great time but its probably not mdma. Ill link you to erowids foxy page, the picture looks exactly like the "sass" I had.
https://www.erowid.org/chemicals/5meo_dipt/