SOCOTRA HOQ CAVE-YEMEN
The Hoq Cave is rather easy to enter, and it stretches for about 3-4 km along the cliff. It is rather
cool inside. The ground of the cave is water-free, and there are only terraced plots filled with water
at the end of it. The pathway inside the cave is marked by a reflective tape so it is not possible to
lose your way. Stalagmites and stalactites which have formed over thousands of years are intriguing
but perhaps what impresses the most is the sheer depth and size of Hoq Cave. There is a popular
opinion that Hoq Cave is the largest one on Socotra, but this is not the case, as there are also other
hard-to-reach caves stretching for many kilometers deep into the island. Most of Socotra’s caves
are cool, but still the temperature becomes more humid the deeper you go, and right at the very
end, the deepest point you can go, water fills a terraced plateau.
SOCOTRA HOQ CAVE -LIMESTONE STALAGMITES
Hoq Cave has some truly spectacular stalagmites. The most common stalagmites are speleothems,
which usually form in limestone caves. Stalagmite formation occurs only under certain pH
conditions within the cavern. They form through deposition of calcium carbonate and other
minerals, which is precipitated from mineralized water solutions. Limestone is the chief form of
calcium carbonate rock, which is dissolved by water that contains carbon dioxide, forming a
calcium bicarbonate solution in caverns. If stalactites – the ceiling formations – grow long enough
to connect with stalagmites on the floor, they form a column. Stalagmites should normally not be
touched, since the rock buildup is formed by minerals precipitating out of the water solution onto
the existing surface, and skin oils can alter the surface tension where the mineral water clings or
flows, thus affecting the growth of the formation. Oils and dirt (mud, clay) from human contact can
also stain the formation and change its color permanently.
