Iceland is a geological anomaly, a land mass perpetually under construction where the forces of fire and ice converge. Situated directly atop the Mid-Atlantic Ridge, the island constantly splits apart as the North American and Eurasian tectonic plates drift away from each other. This intense, ongoing volcanic activity creates an environment uniquely suited for forming beautiful and diverse mineral deposits. The rapid cooling of lava flows, followed by geothermal processes, acts as a natural laboratory, transforming chemical elements into crystalline structures. This dramatic setting explains why a relatively young landmass like Iceland is a surprising source of collectible gemstones and minerals.
How Iceland’s Unique Geology Creates Gemstones
The genesis of Iceland’s crystalline treasures is linked to its basaltic bedrock, which makes up roughly 90% of the island’s solid rock. As basalt lava erupts, it traps large quantities of volcanic gases, forming bubbles known as vesicles. When the lava solidifies, these vesicles become small, empty cavities that are perfect sites for mineral growth.
The next stage involves the island’s geothermal activity, which drives mineral-rich hot water through the cooled, fractured basalt. Over millions of years, these hydrothermal fluids circulate through the rock, dissolving elements and precipitating new compounds inside the empty gas pockets. This process creates secondary minerals, which are deposited layer by layer, filling the voids with crystalline material. The resulting structures are often geodes or almond-shaped amygdules, housing the colorful quartz and zeolite varieties that collectors seek.
Icelandic Spar The Island’s Signature Mineral
Among Iceland’s geological finds, a transparent form of Calcite known as Icelandic Spar, or Silfurberg in Icelandic, holds a special place. This mineral is a pure variety of calcium carbonate, characterized by its perfect rhombohedral cleavage, causing it to break into distinctive parallelogram shapes. Its most famous property is strong double refraction, or birefringence, where light entering the crystal is split into two separate rays.
Viewing an object through Icelandic Spar makes the image appear doubled, an effect that captivated scientists like Christiaan Huygens in the 17th century and helped advance the study of light polarization. The mineral was historically sourced from the Helgustaðir mine in East Iceland, which supplied optical-grade material to the world for centuries. Some researchers speculate that this optical property allowed Vikings to use the spar as a “sunstone,” helping them navigate the cloudy North Atlantic by locating the sun’s position.
Common Minerals Found in Basalt Flows
Beyond the clarity of Calcite, the basalt flows are rich with various forms of silica that have solidified into striking, colorful minerals. Agate, a banded variety of Chalcedony, is a common find, formed as silica-rich water deposits concentric layers inside basalt vesicles. These often display reds, oranges, and browns from iron oxides present in the surrounding rock. Jasper, another microcrystalline quartz variety, is also widely distributed, frequently showing opaque red, yellow, or green hues due to impurities and volcanic ash layers.
In addition to the quartz family, a large group of hydrated aluminosilicate minerals known as Zeolites form beautiful, delicate crystals within the basalt cavities. Species such as Stilbite and Heulandite are known for their distinct, often glassy crystal habits, appearing as sheaf-like bundles or tabular plates in shades of white, pink, or yellow. Volcanic glass known as Obsidian is also abundant, particularly in areas of rapid-cooling basaltic eruptions. While not a true crystal, this black, glassy rock forms when lava cools too quickly for crystals to develop, resulting in a dark, lustrous material.
Where to Find and View Icelandic Gemstones
The most celebrated region for finding Iceland’s minerals is the East Fjords, where the older Tertiary basalt formations are exposed and eroded by glaciers and the sea. Coastal towns like Stöðvarfjörður and Djúpivogur are known to be rich in Agate, Chalcedony, and Zeolites, often found weathering out of the basalt cliffs. The best way for visitors to appreciate the full spectrum of Icelandic stones is through dedicated collections and museums.
Petra’s Stone Collection in Stöðvarfjörður is a famous stop, showcasing the life’s work of a local woman who gathered thousands of specimens from the surrounding area. Collecting is strictly regulated; removing stones from national parks, protected sites like the former Icelandic Spar mine at Teigarhorn, or private land is prohibited. Tourists are strongly encouraged to view the minerals in museums or purchase legally sourced specimens from authorized local vendors.