Volcanic Gems in Lava Flows: Unearthing Peridot and Other Fiery Treasures

For rockhounds and mineral collectors, the thrill of discovering a unique specimen is unmatched. Among the most sought-after treasures are volcanic gems found in lava flows, with peridot leading the pack. This article delves into the origins, characteristics, and collecting tips for peridot and its volcanic companions.

The Formation of Volcanic Gems

Volcanic gems are formed from the cooling and solidification of molten lava, which contains various minerals. As lava flows, it can trap and crystallize elements conducive to gem formation. For example, peridot–one of the few gems that occurs in volcanic rock–forms in the Earths upper mantle and is brought to the surface during volcanic eruptions.

What is Peridot?

Peridot, also known as the evening emerald, manifests in a range of green hues due to the presence of iron. The color can vary from yellowish-green to deeper green, depending on the iron content. With a hardness of 6.5 to 7 on the Mohs scale, it is relatively durable, making it suitable for various jewelry applications. Peridot is primarily found in:

Hawaii, where it is known as â€œolivineâ€ in its natural state.
The lower mantle of Earth, surfacing through volcanic activity.
The San Carlos Apache reservation in Arizona, one of the largest producers in the United States.

Other Volcanic Gems

Besides peridot, lava flows also produce several other notable minerals and gemstones. These include:

Obsidian: A naturally occurring glass that forms when lava cools quickly. Collectors appreciate its sharp edges and unique reflective properties.
Pumice: While often overlooked, pumice can form intriguing shapes and textures, making it a collectors item.
Basalt: Found in massive lava flows, basalt is rich in iron and magnesium and can exhibit interesting structural formations.
Perlite: A volcanic glass that expands upon heating, often used in horticulture and as a soil amendment, but also collected for its unique appearance.

The Science Behind Volcanic Gem Formation

The diverse mineral content of lava plays a crucial role in gem formation. The temperature and pressure conditions during volcanic eruptions can significantly affect the crystallization process. For example, gem-quality peridot typically crystallizes at depths of 20 to 55 kilometers beneath the Earthâ€™s surface before being erupted by volcanic forces.

The average size of peridot crystals found in lava ranges from 1 to 4 centimeters, though larger specimens have been documented. Collectors often seek peridot in basalt rock where it can be found as small, gem-quality crystals. Regular exposure to weathering processes can also enhance the visual appeal, creating a polished gem appearance.

Practical Tips for Collectors

For those looking to add volcanic gems like peridot to their collections, here are some actionable tips:

Research Local Areas: Many states have designated rockhounding locations where volcanic gems can be found. Check geological maps and local resources to identify potential sites.
Attend Rock Shows: Trade shows and rockhound conventions often feature vendors selling volcanic gems and minerals, providing opportunities to purchase high-quality specimens.
Bring the Right Tools: Essential tools for collecting include a rock hammer, chisels, safety goggles, and a sturdy backpack to carry your finds.
Join Local Clubs: Rockhounding clubs can provide valuable insights and access to group outings, enhancing your chances of discovering unique gems.

Conclusion

Uncovering volcanic gems like peridot is not just about the thrill of discovery; it is also an exploration of Earths geological processes. With the right knowledge and tools, rockhounds and mineral collectors can uncover these fiery treasures that tell a story of natural wonder.

In summary, while peridot is a standout gem among volcanic finds, other equally fascinating minerals await discovery. By understanding the formation and characteristics of these volcanic gems, collectors can better appreciate their unique beauty and incorporate them into their prized collections.