Here is a brief description of curium. If curium enters the body it accumulates in the bones, and is therefore very toxic as its radiation destroys the red-cell forming mechanism.
Curium is a radioactive rare earth metal.
The most stable isotope is 247 Cm which has a half-life of 16 million years. Curium is probably present in uranium ores. It has a few specialised uses but only a few of its compounds are known. Here is a brief summary of the isolation of curium.