Image 1 of 3
Image 2 of 3
Image 3 of 3
In 2021, Gemrock Peru "mined" Black Tourmaline in the desert mountains of Lima province. They are actually surface collected (Rockhounding). No dynamite or chemicals were used, and no habitat was destroyed.
Location:
The area where this crystal was collected is located in the Andean Foothills to the east of Peru’s capital Lima, at an altitude of approximately 2400 meters. The area is a skarn area.
Geological Formation:
Most skarns form when carbonate rocks such as limestone, dolostone, or marble are intruded by a magma body and altered by contact metamorphism and metasomatism. At the time of intrusion, the heat of contact metamorphism is the primary agent of change.
Then, as the magma cools, it releases hot, acidic, silicate-rich fluids. When this water is expelled from the magma, it is a solvent that has the ability to carry heat and chemically active solutes into the country rock. The water leaving the magma moves through the surrounding rock by flowing or diffusing through pore spaces, fractures, and even the mineral grains that make up the rock. As it invades carbonate rock, the hot, acidic, metal-laden water dissolves, replaces, recrystallizes, and alters minerals in the carbonate rock. These acidic waters are superheated and supersaturated with dissolved metal ions, especially calcium and silicon. As the acidic water moves through the carbonate rocks, its temperature falls and its acidity is neutralized.