Ghar al Hibashi (sometimes spelled Hebashi) is a lava cave situated near the center of Harrat Nawasif/

Al Buqum, a field of vesicular basaltic lava flows located east of Makkah in the Kingdom of Saudi

Arabia. The cave lies approximately 6-7 m below the surface and contains 581 m of mainly rectilinear

passages. Apart from lava stalactites, stalagmites and columns, Hibashi Cave contains many bones and

the desiccated scat of hyenas, wolves, foxes, bats, birds and domestic animals, most of which has been

well preserved due to the cave’s temperature of 20-21°C and humidity of 48 percent. A human skull

425 years old and a man-made wall were found in the cave, but no archeological studies have been

carried out. It is estimated that the cave may be 1.1 million years old.

Two large bat guano deposits in this cave caught fire at some point in the past, heating and

partially burning animal bones and rocks lying on the guano surface and possibly affecting "biostalactites"

thought to be formed of bat urine. These soft, yellowish, accretions, 4 cm or less in length

and up to 1 cm in width, are found throughout the cave.

A few samples of secondary chemical deposits were collected mainly from the burnt guano

areas for mineralogical analysis. Despite the scarcity of these samples, at least 19 different minerals

were detected, most of which are related to the biogenic mineralization of bones and guano deposits.

Three of them, pyrocoproite, pyrophosphite and arnhemite are extremely rare organic compounds

strictly related to the guano combustion, which have been observed until now only in a few caves in

Africa. Ghar al Hibashi may now be considered one of the richest known mineralogical shelters of the

Arabian Peninsula, for which reason it has been included in the list of the ten minerologically most

important lava caves in the world.

The original floor of Hibashi Cave is covered with a layer of fine (10 micron particle size) silt

or loess, dominated by quartz, feldspar and kaolin, extending to almost every point in the cave. This

silt is up to 1.5 m deep and was OSL-dated at 5.8±0.5 ka BP at its lowest level. Because similarly

fine material is often blown about on the surface of Mars, researchers planning for the exploration

of Martian lava tubes are using photographs and maps of Hibashi Cave to produce robotic motion

simulations for testing the capabilities of microrobotic designs to navigate inside the caves of Mars.

The potential also exists to study phytoliths, found inside plant material preserved in animal

scat abundantly available in Ghar al Hibashi, in order to learn more about past flora of the Arabian

Peninsula as well as the process of desertification.