High in the mountains of Switzerland a mineral collector has found a promising spot. From experience he knows that quartz-veins in this area often contain cavities. He works patiently hour after hour, using hammer, chisel and crowbar to pry open the numerous fissures and cracks in the hard rock. Finally, a crack begins to widen. Will it lead to a cavity? Or even to a large cave full of sparkling crystals?
This is not just a rockhound’s dream—it has happened before! One
of the largest such finds on record was made in the summer of 1719, when
a huge crystal cave was discovered in the Grimsel mountain range of
Switzerland. It measured over 140 feet (40 m) in length and had a height of
up to 20 feet (6 m). More than 200,000 pounds of clear quartz crystals
were removed from the cave, including individual specimens with a weight
of up to 900 pounds.
Millions of years ago, this treasure chamber had been an empty rock
cavity buried under thousands of feet of stone, and filled by hot water of
about 2000° F (1200° C) with dissolved silicon dioxide. As geological
events pushed the Earth’s crust upwards and formed mountains, the water
in our rock cavity cooled down, and crystals of silicon dioxide—or “quartz”
—began to grow. But thousands of feet of rock still lay on top of them
which had to be broken apart and carried away by the forces of erosion.
Heat and cold, rain and ice removed one foot of rock every 600 years.
Finally, after millions of years, the sound of hammer blows breaks the
silence, and light falls into this ancient treasure chamber.
Few ever experience such a thrilling moment of discovery since large
caves full of crystals are of course very rare. But smaller cavities are fairly
frequent, and if you start collecting minerals, you will sooner or later find
a miniature crystal cave: a “geode.” From the outside it looks like an
ordinary boulder which was rounded in a river. But it is hollow and therefore
much lighter. Crack it open with hammer and chisel, and you will look
into a small cave filled with magnificent sparkling crystals!