* Extrusive Igneous Rock: This means the rock formed from lava that erupted onto the Earth's surface.
* Basalt: Basalt is a common extrusive rock with a fine-grained texture. It often has a smooth surface and small, scattered holes (vesicles) formed by escaping gas during cooling.
Other possibilities:
While basalt is the most likely candidate, there are a few other possibilities:
* Andesite: A similar volcanic rock with a slightly higher silica content. Andesite can also be smooth and have small vesicles, but it tends to be a bit darker in color than basalt.
* Rhyolite: This rock is more felsic (higher silica content) and is usually light-colored with a glassy texture. It can also form with small vesicles, but it's less common to find rhyolite with a smooth surface.
To further confirm the type of rock, you can:
* Look at the color: Basalt is typically dark gray to black.
* Feel the texture: Basalt is typically dense and heavy.
* Examine the vesicles: The size and shape of the vesicles can provide clues.
It's best to consult a geologist or a rock identification guide for a definitive classification.
