If a person were to come into contact with lava, the extreme heat would cause severe burns and likely be fatal. However, it would not turn a person into stone in the way that mythological creatures or folklore suggest. The idea of turning into stone when coming into contact with lava is a misconception.
When magma reaches the surface it is then called lava and the eruptions of lava and ash produce volcanoes. The lava that reaches the Earth's surface will harden and become igneous rock.