Five meteorites in the world carry the classification Lunar (troct. anorth. melt breccia), and each has one recorded main mass. This is the main mass of Northwest Africa 18211: a single lunar stone of 2,524 g, offered by private treaty to institutions and collectors.
The difference reflects removal of a thick caliche layer in the lab and withdrawal of the 20.14 g type specimen. The Bulletin records the meteorite as one piece. The only cut on the stone is the one made to remove the type specimen for classification.
What this stone is
Northwest Africa 18211 is a piece of the lunar highlands crust. The Meteoritical Bulletin classifies it as Lunar (troct. anorth. melt breccia): rock formed when an impact on the Moon melted and mixed plagioclase-rich crust with fragments of olivine-bearing troctolite, then cooled into a new, welded rock.
Under the microscope, the classifying petrographer describes mineral debris and sparse troctolitic clasts set in a plagioclase-rich, partly devitrified impact melt matrix. The plagioclase is highly calcic, at An97.9, which is characteristic of lunar anorthosites. Olivine and pigeonite FeO/MnO ratios recorded in the entry (91 and 58) fall in the range used to distinguish lunar material from other achondrites.
One of five main masses
As of September 2026, the Meteoritical Bulletin lists this as 1 of 5 approved meteorites classified as Lunar (troct. anorth. melt breccia). Every approved meteorite has a single recorded main mass, so for this classification there are five, held by five different parties. A collection or museum that wants the principal specimen of one of these meteorites is choosing from that list and no other.
Of the five, the Bulletin records only two as a single stone. Northwest Africa 18211 is one of them. The others were recovered as two stones, several pieces, or multiple stones.
| Meteorite | Total known weight | Pieces recorded |
|---|---|---|
| Northeast Africa 089 | 16 kg | Several; largest fragment 12.9 kg |
| Northwest Africa 17295 | 11,765 g | 1 |
| Northwest Africa 17865 | 10,200 g | 2 (5,951 g and 4,249 g) |
| Northwest Africa 18211 | 2,576 g | 1 |
| Oued Tilemsi 003 | 777 g | Multiple |
Figures from each meteorite's Meteoritical Bulletin entry, September 2026. Northeast Africa 089 and Oued Tilemsi 003 are listed under Meteoritical Bulletin 115, in preparation. The count of five will change if further meteorites receive this classification, and entries are counted separately until pairing is established: the Bulletin notes Northwest Africa 18211 is likely paired with Northwest Africa 17706, which is classified simply as Lunar.
The Bulletin record
Full entry: Meteoritical Bulletin Database, Northwest Africa 18211.
Where it sits among lunar meteorites
By recorded total known weight, Northwest Africa 18211 ranks 117th of 830 lunar entries in the Meteoritical Bulletin Database, which places it above roughly 86 percent of them. That ranking is taken from the database update of 21 August 2026 and is maintained on our largest lunar meteorites reference, where the method and its limits are set out in full.
The number that matters most to a buyer is a different one. Large lunar meteorites are usually recovered as many fragments or sectioned soon after purchase, so a high total known weight rarely means a large intact piece exists. This meteorite is recorded as a single stone, and the stone we hold is that stone, less its caliche and type specimen.
One of, if not the largest, single-stone lunar meteorites currently offered for private acquisition.
In September 2026 we reviewed the lunar listings of major meteorite dealers and recent auction catalogues. Publicly listed lunar material was almost entirely slices, end cuts and fragments under 100 g, and the largest lunar piece in a spring 2026 auction weighed under 800 g. We found no lunar stone of comparable size publicly listed. Larger lunar stones do exist in private hands and occasionally come to market through auction or private sale, so this is a statement about what we have been able to find, not a published ranking, and we would welcome a correction if one is due.
Documentation
The stone carries serial TC-00009 in our specimen registry. Its specimen record sets out the photographs and weight used to identify it. The record is a reference document, not a certificate of authenticity or an appraisal; the classification itself rests on the Bulletin entry above.
Acquisition
Northwest Africa 18211 is offered by private treaty. The price is provided on request to institutions, collectors and their representatives. Inspection, additional photography and delivery arrangements are handled directly with Brian McDonald.
Fully insured personal delivery to approved destinations is available through our white glove service, arranged on request.
Frequently asked questions
- Is Northwest Africa 18211 a real lunar meteorite?
- It is an official meteorite name, classified as Lunar (troct. anorth. melt breccia) by J. Garcia at ADARA and published in Meteoritical Bulletin No. 114. The classification rests on petrography and mineral chemistry recorded in the Bulletin entry, including plagioclase at An97.9 and olivine and pyroxene FeO/MnO ratios.
- How large is it?
- The Bulletin records a total known weight of 2,576 g in one piece. The stone held by Treasure Coast Meteorite Co. weighs 2,524 g, after removal of the caliche layer and the 20.14 g type specimen.
- How many meteorites share this classification?
- As of September 2026, the Meteoritical Bulletin lists 5 approved meteorites classified as Lunar (troct. anorth. melt breccia). Each has one recorded main mass. Northwest Africa 18211 is one of two recorded as a single stone, and its main mass is the stone offered on this page.
- Can it be bought?
- Yes, by private treaty. Lunar meteorites arrived on Earth naturally and can be privately owned, unlike Apollo samples. See can you legally buy a moon rock. The price is available on request.
- What does troctolitic anorthosite melt breccia mean?
- Anorthosite is rock made mostly of plagioclase feldspar, the main component of the lunar highlands. Troctolitic indicates olivine is present alongside it. A melt breccia is rock in which fragments are held together by material melted in an impact. Our guide what is a lunar meteorite covers the wider background.
- Is it related to other meteorites you hold?
- The Bulletin states that Northwest Africa 18211 is likely paired with Northwest Africa 17706 and belongs to the same batch of rocks collected by the finder. Slices of Northwest Africa 17706 are listed in our lunar meteorite collection.
- Is white glove delivery available?
- Yes. Fully insured personal delivery to approved destinations can be arranged. Details are on the white glove service page.
