Or not. Using it to refute the age of an artifact is entirely different from using it to affirm the age of an artifact.
Carbon dating has numerous problems and so does radiometric dating. When an Hawaiian lava flow, known to have occurred in 1801, was tested, twelve times, twelve different results were reached, all varying wildly, none accurate, ranging from 140 million years to nearly 4 billion years, with an average between the twelve of 1.46 billion years. It was less than 200 years old at the time.
Rock is not carbon dated. C14 has a half life of about 6000 years; radioisotope dating is mostly accurate within the first 6 or so half lifes (~36,000 years for C14). Also, you have to remember, that even if the volcano erupted 200 years ago, the rock that emerged is as old as the earth.