Crystal cartridges are basically like a capacitor. So you need a very high input impedance. Like 2 Meg ohm or 1 Meg Ohm.Almost never found in most home audio equipment. If the input impedance goes down to 500K it will start to sound lighter in the bass. Output levels depends on the model and can vary typically from about 150mV to 1 V or so. Some people do connect it to a MM phono cartridge input with a capacitor in series ( 100pF ~250pF ) and 100K or 47 K impedance. Partly compensating for the bass boost of the usual MM RIAA equilisation.But it will be a problem to make it sound as good as an inexpensive MM cartridge ! There was a ceramic cartridge with 20mV output which supposedly sounds good. But I guess you have a cartridge and just want to use it. If you want better sound then you will have to use a MM phono cartridge. We started into hi-fi with ceramic cartridges and progressed to MM and never looked back ! If you have lots of time to experiment it can be exciting. But if you just want good sound don't waste your time on it.
Look at the following info : http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1971/Ceramic Pickup Equalisation.pdf