NWA 18497 CVox3 Carbonaceous Chondrite Main Mass Complete Stone 443.52g

The main mass of NWA 18497, an oxidized CV3 carbonaceous chondrite, as a complete stone

NWA 18497 belongs to the CV group of carbonaceous chondrites, primitive stony meteorites that preserve solids from the earliest stage of the solar system. This 443.52 gram stone is offered as it was received: complete, with no saw cuts, no polished face and no slices removed. Chondrules in tan, orange and copper tones show across its natural exterior, set in a dark matrix, and stand out in relief on the rougher faces of the stone. Remnants of fusion crust remain on parts of the exterior.

The Meteoritical Bulletin lists NWA 18497 as CVox3 with a recorded mass of 725 grams in many pieces, and records the main mass with Brian McDonald. This stone is that main mass. It was classified by J. Garcia, ADARA, under the workname BMD 038.

Structure and features

Because the stone has never been cut, everything visible is natural surface. Remnants of fusion crust, dark and glossy, remain on parts of the exterior, alongside lighter, chondrule-rich surfaces on the long faces and ends where the interior texture shows through. The stone carries no coating. Rounded chondrules are visible to the eye across these surfaces, and fine cracks and thin pale veins cross the exterior in places.

One face carries a pale, elongated inclusion several millimeters long, cream colored with orange staining. Its appearance is consistent with the calcium-aluminum-rich inclusions (CAIs) the Bulletin describes in this meteorite, but it has not been analyzed and is not identified here as a CAI.

The classification thin section, described in the Bulletin, shows well-defined chondrules in a dark, fine-grained, olivine-rich matrix. Chondrules have an apparent mean diameter of about 1.2 mm and are dominated by Type I chondrules, with Type II chondrules extremely scarce. Most show porphyritic textures, both porphyritic olivine and porphyritic olivine-pyroxene, with minor barred olivine. Amoeboid olivine aggregates are present, and CAIs range from submillimeter to almost a centimeter, including one of about 9 mm in the analyzed section. The Bulletin records a low weathering grade.

Discovery and provenance

NWA 18497 carries a Northwest Africa name, used for meteorites from the region whose exact find site is not documented. The Bulletin records the year as 2024, and its writeup states the meteorite was purchased in 2024 from an Algerian dealer. Coordinates are recorded as unknown.

The Bulletin records the workname BMD 038 and lists the meteorite as submitted by Jose Garcia. J. Garcia at ADARA in the Canary Islands carried out the petrography and classification. A 20 gram type specimen is held at MUNA, the Museo de la Naturaleza y Arqueologia in Tenerife, and one thin section is held at ADARA. The entry was approved on 27 March 2026 and is listed for Meteoritical Bulletin 115, which is in preparation and not yet a published volume.

The Bulletin records the main mass of NWA 18497 with Brian McDonald. Identification of this 443.52 gram stone as that main mass comes from Treasure Coast Meteorite Co. records. The recorded mass of 725 grams covers the meteorite as a whole, across many pieces, and is not the weight of this stone.

Scientific context

CV chondrites are among the most studied carbonaceous chondrites. They are known for large chondrules, abundant matrix, amoeboid olivine aggregates and CAIs, the last being among the oldest dated solids formed in the solar system. NWA 18497 shows each of these features in its classification section. Background on the wider family is set out in what is a chondrite.

The "ox" in CVox3 places NWA 18497 in the oxidized subgroup of the CV chondrites, as distinct from the reduced subgroup. The classifier assigned this on the mean nickel content of its sulfides and metal: sulfides average 4.1 wt% Ni and metal 65.8 wt% Ni. The "3" is the petrologic type, assigned on the strong compositional heterogeneity of its olivine and pyroxene. Chondrule olivine averages Fa8.6 and matrix olivine Fa49.9. How these designations are assigned is covered in how meteorites are classified.

What the research reports

The Meteoritical Bulletin's recommended classification for NWA 18497 is CVox3. Its writeup goes one step further and classifies the meteorite as CVoxA3, placing it in the Allende-like branch of the oxidized CV chondrites, on the basis of the criteria in the study below. The recommended class is what appears in this listing's title and metafields; the CVoxA assignment is given here as the writeup states it. Findings below come from the authors' own samples and methods and are given as the study states them.

Gattacceca, Bonal, Sonzogni and Longerey (2020)

J. Gattacceca, L. Bonal, C. Sonzogni and J. Longerey, CV chondrites: More than one parent body, Earth and Planetary Science Letters 547, 116467 (2020). This is the study the Bulletin writeup cites for the CVoxA assignment.

The authors studied 53 CV chondrites, sorting them into the reduced subgroup and the two oxidized subgroups, CVoxA and CVoxB, and measuring chondrule sizes, matrix abundance and, for 17 of them, oxygen isotopes. They found that the reduced and oxidized CV chondrites differ in chondrule size and matrix abundance, and concluded that the two come from distinct parent bodies, while CVoxA and CVoxB likely share one. In their words, CVoxA chondrites represent "deeper, more metamorphosed levels than CVOxB chondrites." They proposed treating CVox and CVred as two separate groups rather than subgroups, and showed that the two can be told apart by the average nickel content of their sulfides, the method used for NWA 18497. That proposal is the authors' own; the Bulletin continues to record the subgroup within the CV group.

Frequently asked questions

Is this the main mass of NWA 18497?

The Meteoritical Bulletin records the main mass of NWA 18497 with Brian McDonald. This 443.52 gram stone is that main mass, per Treasure Coast Meteorite Co. records.

Has this stone been cut or polished?

No. It is a complete stone with no saw cuts and no polished face. Every surface shown in the photographs is natural exterior.

Does the stone have fusion crust?

Yes. Remnants of fusion crust, the glassy skin formed as the meteorite passed through the atmosphere, remain on parts of the exterior. The stone is not coated.

What does CVox3 mean?

CV is the carbonaceous chondrite group, named for the Vigarano meteorite. "ox" marks the oxidized subgroup, assigned for NWA 18497 on the nickel content of its sulfides and metal. "3" is the petrologic type, indicating the least thermally altered chondrites. The Bulletin writeup further assigns it to the CVoxA branch, following Gattacceca and colleagues (2020).

Is the pale inclusion on the surface a CAI?

It has the general appearance of the CAIs the Bulletin describes in this meteorite, which reach almost a centimeter, but this particular inclusion has not been analyzed. It is described as a pale inclusion, not as a confirmed CAI.

Is the 725 gram figure the weight of this stone?

No. 725 grams is the recorded mass for the meteorite as a whole, which the Bulletin lists as many pieces. This stone weighs 443.52 grams.

Has NWA 18497 been published?

The entry was approved on 27 March 2026 and is listed for Meteoritical Bulletin 115, which is in preparation. The classification is official; the volume is not yet published.

Who is the seller?

Treasure Coast Meteorite Co., IMCA Member #3323, Hobe Sound, Florida. Background on the Bulletin and what its entries record is in understanding the Meteoritical Bulletin.

Collector significance

This is the main mass of an officially classified CV3 chondrite, and it has been left whole. It keeps its full natural form, with no face removed, so the stone can be studied, displayed or kept in its natural state.

As of November 2026, the Meteoritical Bulletin lists this as 1 of 67 approved meteorites classified as CVox3.

This specimen is offered by Treasure Coast Meteorite Co., IMCA Member #3323, and is issued with a permanent specimen record and serial number. Browse more carbonaceous chondrites, chondrites and stony meteorites in the collection.

Classification and provenance for this specimen follow the official Meteoritical Bulletin entry for NWA 18497, viewable at the Meteoritical Bulletin Database.