Here is the full list of all 17 Word Crystal achievements.
Found a word on the sixth guess.
Found a word in five guesses.
Found a word in one guess.
Found a word in two guesses.
Found a word in three guesses.
Found a word in four guesses.
Lost a puzzle.
Won a puzzle.
Won five puzzles.
Won 10 puzzles.
Won 25 puzzles.
Won 50 puzzles.
Puzzles won two days in a row.
Puzzles won three days in a row.
Puzzles won six days in a row.
Puzzles won ten days in a row.
Puzzles won twenty days in a row.