. I am described as being conductive, malleable, shiny, and reactive with HCl. I am one of the most reactive elements. I turn black with

. I am described as being conductive, malleable, shiny, and reactive with HCl. I am one of the most reactive elements. I turn black within seconds when I am exposed to air. If someone drops water on me, I will explode. When I do explode I send off characteristic purple-red (violet) flame. Who am I?