Komatiite Large Spinifex Blades S. Africa [154 gm ~ 3.5 Ga]

Komatiite from the Pioneer Ultramafic Complex 154 gm

This rare mantle-derived volcanic rock, known as komatiite, originates from the Pioneer Ultramafic Complex, Weltevreden Formation, Barberton Greenstone Belt in South Africa. It stands out for its large, stunning bladed forsteritic olivine crystals with vibrant green hues and a prominent, easily visible spinifex texture—a hallmark feature of komatiites that showcases their rapid cooling process. The front and back of the specimen are lightly coated, while the exterior crust is superb. An XRF analysis is included!

What is Komatiite?

Komatiites are a type of lava. Specifically, they are ultramafic volcanic rocks formed from extremely hot, low-viscosity lava. Komatiite formed under much hotter conditions (up to 1600°C) than most modern volcanic lavas, which typically form at temperatures below 1300°C.

Komatiites were primarily produced during the Archean Eon (4.0 to 2.5 billion years ago), when the Earth's mantle was significantly hotter. They are an igneous ultramafic rock of volcanic origin, renowned for its high magnesium content and extremely low levels of silicon, potassium, and aluminum. This unique composition makes komatiite one of the rarest types of volcanic rock on Earth. True komatiites are exceedingly rare and only found in ancient geological settings. They are confined to Archean shield regions where some formed as long ago as ~3.8 Ga (Faeringhavn Komatiite - the oldest) and like this terrific specimen at ~3.5 Ga.

What is the Composition of Komatiite?

The mineralogical composition of komatiite is fascinating, with a blend of forsterite olivine, chromian pyroxene, anorthite, and chromite - all preserved in its striking spinifex bladed texture. This texture forms as the lava cools rapidly, creating long, needle-like crystals that fan out in a unique pattern. Named after the Komati River, where it was first discovered, komatiite is believed to be between 3.5 - 3.2 Ga. This age marks it as a relic from a time when the Earth’s mantle was different from today, giving rise to these distinctive ultramafic volcanic rocks.

Geological Significance

Komatiites provide an exceptional window into early Earth’s volcanic activity, helping scientists understand the conditions of the early mantle and the tectonic processes that shaped our planet. Their presence is also closely associated with the formation of important mineral deposits, particularly nickel and gold. This makes them highly sought after, not only for scientific research but also by collectors, who value their rarity and significance.

Specimen Details

• Size: 73mm L x 75mm W x 15mm D
• Weight: 154 grams
• What's Included:  A Certificate of Authenticity, detailed information about komatiite, tag, tag stand, and XRF report are all included. (Acrylic base and photo cube not included.)
• Additional Information: Polished smooth both sides. Great texture, form and crust! No repairs, stable specimen.

Why are Komatiites a Must-Have for Collectors?

Komatiites are not only geologically rare, but they also hold significant economic importance due to their association with rich nickel and gold deposits found in regions such as Australia, Greenland, South Africa, and the Guiana Shield of South America. 

For collectors and enthusiasts alike, this komatiite is a prized addition to any collection. Its rarity, striking appearance, and the insights it offers into the Earth’s early volcanic activity make it a unique and valuable piece of geological history. Whether for display or research, this specimen offers a rare glimpse into the distant past of our planet’s dynamic geological evolution.