Shellac records need different replaceable needles, because fine pieces of grit are embedded in the record to harden it and wear down the needle. Needed because

Shellac records need different replaceable needles, because fine pieces of grit are embedded in the record to harden it and wear down the needle. Needed because the tracking force was so high back in the day. Modern records use a so-called "microgroove", usually crystal needles in the cassette, and one or so grams of tracking force. You probably wouldn't pick anything up off a shellac record, if you tried playing it.