What is the texture of basalt?
Porphyritic Basalt
| Type | Igneous Rock |
|---|---|
| Texture | Porphyritic |
| Origin | Extrusive/Volcanic |
| Chemical Composition | Mafic |
| Color | Dark Gray to Black |
What are basalt characteristics?
basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium. Basaltic lavas are frequently spongy or pumiceous; the steam cavities become filled with secondary minerals such as calcite, chlorite, and zeolites.
What does basalt look like?
Basalt is usually dark grey to black in colour, due to its high content of augite or other dark-coloured pyroxene minerals, but can exhibit a wide range of shading. Some basalts are quite light-coloured due to a high content of plagioclase, and these are sometimes described as leucobasalts.
Is basalt coarse or fine-grained?
Basalt is a fine-grained mafic igneous rock. It is commonly vesicular and aphanitic.
Is basalt smooth or rough?
‘A’a basalts have rough surfaces (that make barefoot people cry, “Ah! Ah!” as they walk across it). They form from fast flowing lava. Pahoehoe basalts have a smooth glassy surface that looks like many ropes.
Is basalt fine or coarse grained?
Is basalt hard or soft?
Basalt is a hard, black volcanic rock. Basalt is the most common rock type in the Earth’s crust.
Is basalt a soft rock?
Is basalt porous?
It can have a glassy appearance. There are many types of basalt with different proportions of elements. It may be compact or vesicular (porous) because of gas bubbles contained in the lava while it was cooling.
Does basalt have a smooth texture?
Basalt forms when lava reaches the Earth’s surface at a volcano or mid ocean ridge. The lava is between 1100 to 1250° C when it gets to the surface. Pahoehoe basalts have a smooth glassy surface that looks like many ropes. The “ropes” form when the surface cools, becoming solid rock while lava flows beneath it.
Why is basalt so hard?
Basalt is a hard, black volcanic rock with less than about 52 weight percent silica (SiO2). Because of basalt’s low silica content, it has a low viscosity (resistance to flow). Therefore, basaltic lava can flow quickly and easily move >20 km from a vent.