Heck yeah you can start another plant! It's easier to start jade from stems than leaves anyway. I'm fairly sure you do it just like any other succulent..Let it sit for a bit to callus over then use rooting hormone and some people root in sand first..not letting it dry out completely. But I know someone will give you better specifics than that, I'm new to propagation :)
-Dani

We have so many Jade plants now - all came from one plant!

My brother, I don't think he even used a hormone, he just stuck a piece (sometimes just a leaf and other times a small branch) into a pot in potting soil. That was it and they rooted so fast. They are a pretty interesting plant in that respect. Being it a succulent it would probably be best to put a bag over the pot to keep the moisture in.
They are a darn easy plant to propagate - I'm sure you'll have no trouble.

Yeah, half the time if a piece of succulent falls off, it will root whether you want it to or not. I think the rooting hormone is more to make it root faster.

Stem segments, stems w/leaves, or leaves can be rooted with nothing more than a potting media and occasional water. Make sure to allow the "cut" end/s callus for 2-3 days and plant. Check on them every two wks. or so, watering then.

wow - thanks for the above.. my jade is over 6'+ tall jade was blown over by hi winds when I opened my slider - broke in half.. makes me sick, in full bloom - gorgeous.. so, I repotted the 4' upper half, in new pot, potting soil.. looks nice, but scared about it.. the original base of the plant, with a 6"+ diameter trunk, is so short.. the part where it broke, is about 4" diameter, hope it makes it. Should I unpot the part I potted, and let it just 'sit' for a few days tho???