I got an adamant from my deep mines today, one from Sir Pig a few days ago after never having gotten any since starting play in October, so maybe the drop rate has improved. If/when I ever get four, I'll finally try to upgrade my deep mines (hate having two mines that have different collection times). Guess I'll try to accumulate enough living wood to make those ornate beams and architect's paste for magic cement since I have no other goals (still no dragon egg).