Basalt is an extrusive igneous rock primarily composed of plagioclase feldspar, pyroxene, and sometimes olivine. It is characterized by a fine-grained or aphanitic texture and typically appears dark gray, black, or dark green in color. As the most common rock type on Earth’s surface, basalt makes up the majority of the oceanic crust. Its low viscosity, high resistance to weathering, and durability make it an important material for construction and infrastructure projects, such as roadways, building stones, and cobblestones.
Mineral Makeup
The mineral makeup of basalt consists of several different minerals, with plagioclase feldspar, pyroxene, and occasionally olivine being the most common. Plagioclase feldspar is a group of minerals that typically appears light to dark gray or white and can be found in basalt as tiny, elongated crystals. Pyroxene, a group of dark-colored minerals, is often black or green and appears in basalt as small, needle-like crystals. Olivine, when present, is a greenish mineral found as small, rounded grains within basalt.
Origin
Basalt forms through the rapid cooling and solidification of molten rock or lava that is rich in iron and magnesium. This rapid cooling process results in the formation of small crystals, giving basalt its fine-grained texture. Basalt is commonly found in areas of volcanic activity, such as along mid-ocean ridges, hotspots, and in continental rift zones.
Occurrence
Basalt is found in numerous volcanic regions around the world, particularly in areas with basaltic lava flows. Some notable occurrences of basalt include the volcanic fields of Iceland, the Canary Islands, the Deccan Traps in India, and the volcanic landscapes of the western United States, such as Craters of the Moon National Monument in Idaho.
Metaphysical
Basalt is believed to possess several metaphysical properties, including grounding, protection, and strength. It is thought to help individuals connect with the Earth’s energy and provide a sense of stability and support during challenging times. Basalt is also said to promote courage and perseverance, helping individuals overcome obstacles and face difficult situations with determination.
| Class | Igneous (Extrusive) |
| Mineral Makeup | Primarily plagioclase feldspar and pyroxene, with possible olivine, amphibole |
| Luster | Dull to vitreous |
| Hardness (Mohs) | 5-6 |
| Streak | White or colorless |
| Color | Dark gray, black, red, or brown |
| Cleavage | Imperfect to good |
| Specific Gravity | 2.8 to 3.0 |
