Yup... unfortunately it will no longer work if the tip is broken. The white stuff is ceramic insulation and it keeps two wires apart until the tip which is called the "hot junction" where they meet. There is also a "cold junction" at the other end which completes the measuring circuit - so in effect the circuit is no longer complete and it will not function at all. Hard to believe there is all that stuff in there and it all knows what to do!