In my crystal set post I use spider coils, because they are easy to make (my 8yo daughter wound one all by herself), and because they have better Q than a TPR coil (Toilet Paper Roll - common type used in basic crystal sets).

s a child, my father got me into building my first crystal set.  I don't fully recall the details, but I seem to recall it was a kitset and I was in Nelson when I built it - If I remember I'll ask him.  What I do remember is building a few of them, including one that fitted inside a tic-tac container and another that had no tuning cap, just an icecream stick with a screw through the end that scratched through to vary the coil windings in use.