Crystal Cave is the most famous of Bermuda’s many subterranean caverns. It is located in Hamilton Parish, close to Castle Harbour. In 1942, Crystal Cave was opened to the public. The entrance to the cave had a full service restaurant that could hold 200 people at one time and on the weekends it served over 1000 people in a day.
The entrance of the cave was closed off by a glass perimeter due to the table cloths turning moldy from the high humidity that the cave produced. In the 1950’s, people realized that parts of the cave would make an excellent fallout shelter so they filled it with food and other necessities.
In 1957, a new section was discovered by using a Brunson and radio receiver on the surface. The area surrounding Harrington Sound (which lies to the south of Crystal Cave) is of limestone formation and noted for many subterranean waterways, through which the waters of the sound empty into the Atlantic. Crystal Cave is one of these, and – as its name suggests – is one of the most spectacularly beautiful, with many stalactites, stalagmites, and deep crystal-clear pools.
The cave’s largest crystal found to date is 12 m (39 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight. The cave is extremely hot, with air temperatures reaching up to 58 °C (136 °F) with 90 to 99 percent humidity.
The cave is relatively unexplored due to these factors. The Cave of Crystals is a horseshoe-shaped cavity in limestone. Its floor is covered with perfectly faceted crystalline blocks. Huge crystal beams jut out from both the blocks and the floor.
The caves are accessible today because the mining company’s pumping operations keep them clear of water. If the pumping were stopped, the caves would again be submerged in water.
The crystals deteriorate in air, so the Naica Project is attempting to visually document the crystals before they deteriorate further. To survive and to be able to work in the extreme temperature and humid conditions which prevent prolonged incursion in the crystal chamber, they developed their own refrigerated suits and cold breathing systems (respectively dubbed Tolomea suit and Sinusit respirator).
Special caving overalls were fitted with a mattress of refrigerating tubes placed all over the body and connected to a backpack weighing about 20 kg (44 lbs) containing a reservoir filled with cold water and ice. The cooling provided by melting ice was sufficient to provide about half an hour of autonomy.
Some rock formations in Crystal Cave are a half-million years old. The lowest point, Devil’s den, is 155 feet (47 m) below the Earth’s surface and in it live thirty to forty% of North American brown bats.
The highest point in the cave is 65 feet (20 m) below the Earth’s surface, in an area that is called “Lookout Point”, for it gives a view of two-thirds of the cave. The cave remains at 52 °F (11 °C), 54 °F (12 °C), and 56 °F (13 °C) in different areas all year round.