NWA 17706 Lunar Meteorite Individual, Troctolitic Anorthosite Melt Breccia, 45.40g, Complete Stone from Earth's Moon

Complete lunar specimen preserving Moon's early crustal history

This 45.40g complete individual of NWA 17706 preserves a complex assemblage of lunar highland materials fused by impact processes on the Moon's surface. The specimen displays the characteristic gray-white coloration of lunar anorthosites mixed with darker melt matrix, revealing the violent collisions that shaped the Moon's crust over billions of years. Recovered from Algeria in 2024 and classified later that year, this stone represents one of the rarest categories of meteorites available to collectors.

The troctolitic anorthosite composition indicates this material originated from the Moon's primordial crust, formed when the lunar magma ocean crystallized approximately 4.4 billion years ago. The melt breccia texture documents subsequent meteoroid bombardment that melted and mixed these ancient crustal rocks. This specimen retains its complete natural form as found, with no cutting or modification, preserving the full context of its ejection from the lunar surface.

Brecciated structure and lunar composition

The specimen exhibits a heterogeneous texture characteristic of lunar regolith breccias, with lighter anorthositic clasts embedded in a darker impact-generated melt matrix. Troctolitic anorthosites contain primarily plagioclase feldspar with olivine, distinguishing them from pure anorthosites that dominate the lunar highlands. These mineral phases crystallized directly from the Moon's initial magma ocean, making them among the oldest rocks in the Solar System.

The melt breccia component formed when micrometeorite impacts partially melted surface materials, welding together fragments of the pre-existing bedrock. This process created the matrix that binds the individual clasts visible throughout the specimen. The fusion occurred on the Moon's surface before a larger impact ejected this material into space, eventually sending it on a trajectory toward Earth.

Scientific context

Lunar meteorites provide direct samples of the Moon's surface without the logistical constraints of space missions. Unlike Apollo samples collected from six equatorial sites, lunar meteorites arrive from random impact locations across the Moon's entire surface. Troctolitic anorthosites represent the Moon's primordial crust, formed when less dense plagioclase floated to the top of the global magma ocean while denser minerals sank to form the mantle. This differentiation process, completed within the first 100 million years of lunar history, created the bright highlands visible from Earth.

The melt breccia classification indicates this specimen experienced significant shock and heating from meteoroid bombardment. These impacts delivered enough energy to partially melt the surrounding rock, creating the matrix that welds together older crustal fragments. Study of lunar breccias helps reconstruct the bombardment history that cratered the Moon's surface and shaped its geological evolution. Collectors seeking to understand planetary formation processes will find detailed information at Learn About Meteorites.

Frequently asked questions

Is this meteorite authenticated? Yes. NWA 17706 received official classification as a lunar troctolitic anorthosite melt breccia and appears in the Meteoritical Bulletin Database: NWA 17706. The specimen includes a certificate of authenticity from Treasure Coast Meteorite Co.

What does troctolitic anorthosite mean? Troctolitic anorthosite is a rock type dominated by plagioclase feldspar (anorthosite) with significant olivine content (the troctolitic component). This composition formed when the Moon's magma ocean crystallized, with these minerals floating to form the primordial crust approximately 4.4 billion years ago.

What is included with this specimen? You receive the complete 45.40g individual meteorite and certificate of authenticity documenting its classification and provenance.

How did this rock get from the Moon to Earth? A large meteoroid impact on the Moon excavated material from depth and ejected it into space at velocities exceeding lunar escape velocity (2.4 km/s). The ejected fragments orbited the Sun until gravitational interactions sent them on Earth-crossing trajectories, resulting in atmospheric entry and recovery in Algeria.

Why is this called a complete individual? This specimen represents an entire fragment as it was found, with no cutting or modification. Complete individuals preserve the full context of their journey through space and atmospheric entry, making them particularly valued by collectors who want specimens in their natural state.

Collector significance

Lunar meteorites comprise less than 0.5% of all classified meteorites, making them among the rarest specimens available. This complete individual offers collectors an unmodified piece of the Moon at a size substantial enough to display the characteristic brecciated texture. The 45.40g mass places it well above the typical fragment size, providing excellent display presence while documenting the Moon's crustal composition and impact history.

The troctolitic anorthosite classification specifically represents the Moon's oldest crustal materials, formed during the magma ocean stage before the late heavy bombardment cratered the surface. Collectors building comprehensive lunar collections or focusing on planetary differentiation processes will find this specimen particularly relevant. Additional lunar specimens and related materials can be explored at Lunar Meteorites.

Meteoritical Bulletin entry: NWA 17706 | Classification: Lunar (troctolitic anorthosite, melt breccia) | Find, Algeria, 2024