What describes metal or rock in a liquid state because of great heat?

The term that accurately describes metal or rock in a liquid state due to extreme heat is "molten." This term specifically refers to the process where solid materials, such as metals or certain types of rocks, reach temperatures high enough to transition into a liquid phase. In geological processes, for example, magma is considered molten rock beneath the Earth’s surface.

The other terms provided do not convey the same meaning. For instance, "solidified" refers to the process of something changing from a liquid back to a solid state, which is the opposite of molten. "Veined" typically refers to a pattern or texture in rock, indicating the presence of different minerals or features, rather than a state of matter. "Fused" can describe materials that have been melted and combined together, but it does not specifically denote the state of being liquid under heat, making "molten" the more precise choice.