* Rocks are made of different minerals: Each mineral has its own melting point.
* Melting point changes with pressure: As pressure increases (like deep within the Earth), the melting point of minerals also increases.
* Presence of water: The presence of water can significantly lower the melting point of some minerals.
Instead of a single melting point, we talk about:
* Solidus: The temperature at which a rock begins to melt.
* Liquidus: The temperature at which a rock is fully melted.
The solidus and liquidus temperatures vary depending on the specific mineral composition of the rock, pressure, and water content.
For example:
* Basalt: A common volcanic rock, begins to melt at around 1000°C (1832°F) at the surface but can melt at lower temperatures with the presence of water.
* Granite: A common igneous rock, has a much higher solidus temperature than basalt, starting to melt at around 650°C (1202°F) at the surface.
In summary: Rocks melt over a range of temperatures, not at a single point. The specific melting range depends on the rock's composition, pressure, and water content.
