Denader 004 Bencubbinite CB Carbonaceous Chondrite Endcut 3.12g

One of nine approved CB carbonaceous chondrites

Denader 004 belongs to a group with only nine approved members in the Meteoritical Bulletin. It is a metal-rich carbonaceous chondrite of the Bencubbin type, built from kamacite metal nodules set in a silicate groundmass of barred and radial chondrules. This specimen is a 3.12 gram endcut, sliced to open the full interior.

The cut face is studded with rounded metal nodules, each ringed by a thin iron hydroxide rim, against a pale gray brecciated matrix flecked with chondrule and mineral fragments. The metal runs through a weathering gradient from silvery to dark to orange limonite, a record of the time the stone spent in the Malian desert before recovery.

What sets this piece apart inside an already small group is the classification itself. A. Greshake could not place Denader 004 in either established CB subgroup. Its silicate fraction, the size of its chondrules, and a fine grained matrix sit it between CBa and CBb, leaving it classified simply as CB.

Structure and features

The cut and polished face presents both halves of the CB texture. Kamacite metal nodules, rounded to slightly elongated and averaging close to 2.5 millimeters across, make up roughly 40 percent of the surface and take a bright reflective polish. The remaining 60 percent is a gray silicate groundmass built from radial and finely barred chondrules up to 4 millimeters wide, broken chondrule and mineral fragments, and a fine grained matrix. Many of the metal nodules carry a thin brown iron hydroxide rim from the meteorite's time in the desert, and small rounded voids mark places where loose metal spheres weathered out. As an endcut, the piece keeps one fully prepared face for viewing while the reverse holds its natural exterior.

Discovery and provenance

Denader 004 was found during a search in Mali in 2025 and purchased from a local dealer near Gao. It was classified by A. Greshake at the Museum für Naturkunde in Berlin and published in the Meteoritical Bulletin, no. 115. The type specimen is held at the Museum für Naturkunde, with the main mass recorded to Jared Collins. The meteorite is listed as a find with low shock and moderate weathering.

Scientific context

CB chondrites, named for Bencubbin, are a metal-rich branch of the carbonaceous chondrites. Their metal and chondrules are interpreted to have formed from a vapor and melt plume thrown up by a high energy collision between early planetary bodies, rather than by the slow condensation that produced most chondrites. That origin is why CB material is dominated by metal nodules and by chondrules with radial and barred textures. The Meteoritical Bulletin entry classifies Denader 004 as CB but does not place it in either established subgroup: a silicate abundance near 60 percent, chondrules reaching 4 millimeters, the presence of a fine grained matrix, and the occurrence of zoned olivine together with ferroan pyroxene do not allow an unambiguous assignment to CBa or CBb. The dominant silicates are enstatite and forsterite, and the metal is a nickel bearing kamacite carrying chromium bearing troilite inclusions.

Frequently asked questions

What is a CB chondrite?
It is a metal-rich carbonaceous chondrite of the Bencubbin type, defined by abundant metal nodules and chondrules. CB chondrites are among the least common carbonaceous groups, with only nine officially classified to date.

Why is Denader 004 not labeled CBa or CBb?
The Meteoritical Bulletin notes that its high silicate content, large chondrules, fine grained matrix, and zoned olivine plus ferroan pyroxene do not fit cleanly into either recognized subgroup, so it is classified as CB without a subgroup.

Will the metal respond to a magnet?
Yes. The nodules are kamacite, a nickel iron metal, so the piece is strongly magnetic.

How should the endcut be stored and handled?
Handle it with clean gloves and keep it in a dry environment. Because it is a moderately weathered desert find that contains metal, low humidity helps protect the cut face and limits further rust.

Why this matters to a collection

CB chondrites record a violent moment in the early solar system, preserving metal and silicate that came together in an impact plume around 4.56 billion years ago. With only nine names classified as CB, the group is seldom offered, and a prepared endcut shows both a full polished face and the natural exterior of the stone. This specimen is offered by Treasure Coast Meteorite Co., IMCA Member #3323.

Classification and provenance for this specimen follow the official Meteoritical Bulletin entry for Denader 004, viewable at the Meteoritical Bulletin Database. Unless specifically stated in titles and descriptions, all meteorites sold by Treasure Coast Meteorite Co. are scientifically classified specimens with Meteoritical Bulletin citations.