METEORITE OR METEORWRONG?
Basalt and related rock types like andesite and dacite are rocks that form when volcanoes erupt magma (lava) onto the surface of the earth and the magma cools.
Basalts come in a wide variety of textures and colors. Some have vesicles (gas bubbles), some don't. Some are gray, others are reddish or even greenish. Basalt is one of the most common rock types on Earth. Except for the coral, all of the rocks of Hawaii are basalts. Much of Oregon and Idaho is covered with basalt.
Basaltic volcanism occured on other terrestrial planets, too. Venus, Mars, the Moon, and some of the largest asteroids had volcanoes that produced basalt. Eucrites are basaltic meteorites from the asteroid belt. About 17% of the Moon is covered with basalt and about 14% of the lunar meteorites are basalts. (See "How Do We Know It's a Rock From the Moon?") Most of the Martian meteorites are basalts (all of those known as shergottites). All basalts, regardless of where they were formed, are similar because the process that formed them (melting in the interior of a planet) is the same. Unfortunately, the only way to distinguish a terrestrial (Earth) basalt from a basaltic meteorite (Moon, Mars, asteroid) is with expensive chemical and mineralogical tests. If you find a basalt, it's probably not a meteorite.
The handful of rocks below came out of a bag sold at a garden shop. They are intended to be used in landscaping or in barbeque grills, where they help distribute the heat evenly. All are vesicular basalts.