Palagonite

Palagonite is an alteration product from the interaction of water with volcanic glass of chemical composition similar to basalt.

The water flashes to steam on contact with the hot lava and the small fragments of lava react with the steam to form the light-colored palagonite tuff cones common in areas of basaltic eruptions in contact with water.

Palagonite soil is a light yellow-orange dust, comprising a mixture of particles ranging down to sub-micrometer sizes, usually found mixed with larger fragments of lava.

Based on infrared spectroscopy, the fine-grained component of Mauna-Kea palagonite is the terrestrial material with the best match to the spectral properties of Martian dust, and is believed to be similar in composition and in origin to dusty component of the surface regolith of Mars.

[1][2] The palagonitic tephra from a cinder cone in Hawaii has been used to create Martian regolith simulant for researchers.