Sinawan 005 Rumuruti Meteorite Slice, R5-6, 23.89g, Dual Lithology Zones

Dual lithology slice from one of three known specimens

This full slice of Sinawan 005 displays two distinct lithological zones separated by a visible boundary -- a light-toned region and a darker domain that reflect heterogeneous metamorphic conditions within the parent asteroid. The contrast between these zones is stark under magnification, offering direct evidence of variable thermal processing or mechanical mixing during parent body history. At 23.89g, this slice captures both lithologies in a single coherent section, preserving the boundary that records localized shock or impact-driven metamorphic gradients.

Sinawan 005 is one of only three classified specimens of this R5-6 type, a transitional metamorphic grade that bridges equilibrated (type 5) and highly metamorphosed (type 6) R chondrites. The dual lithology character visible in this slice suggests localized impact mixing or incomplete thermal equilibration, features that make this specimen scientifically significant beyond its rarity. The surface shows partial fusion crust along one edge, confirming atmospheric entry heating.

Structure and features

The lighter lithology zone exhibits coarser grain structure consistent with type 6 metamorphic grade, where chondrules are partially obliterated and olivine crystals have grown to larger sizes. The darker zone retains finer-grained texture characteristic of type 5 metamorphism, where chondrule outlines remain faintly visible and the matrix has not fully recrystallized. The boundary between these zones is not gradational but sharp, indicating that the two domains were juxtaposed through impact processes rather than gradual thermal transition.

Olivine crystals in both zones display the distinctive high-iron composition that defines Rumuruti chondrites, giving the meteorite its characteristic reddish-brown oxidation state. Small metal grains are sparse, consistent with the highly oxidized formation environment of the Rumuruti parent body. Fusion crust along one edge is thin and dark, with subtle flow lines that record the meteorite's orientation during atmospheric passage.

Scientific context

Rumuruti chondrites represent less than 0.5% of all classified meteorites, making them among the rarest chondrite groups. They formed in an oxygen-rich region of the early solar system, distinct from the more common ordinary chondrites, and likely originated from a single parent asteroid that remains unidentified. The R5-6 transitional grade is particularly scarce -- most Rumuruti meteorites fall cleanly into a single metamorphic type, making specimens that span two grades exceptionally valuable for understanding parent body thermal evolution.

The dual lithology character of Sinawan 005 suggests that the parent asteroid experienced localized impact heating or fragmentation that brought together materials from different thermal zones. This type of brecciation provides a snapshot of internal asteroid structure that would otherwise remain inaccessible. Researchers studying Rumuruti meteorites use specimens like this to model impact processes on small differentiated bodies and to understand how metamorphic gradients develop in asteroid interiors. For collectors and students seeking to understand meteorite petrology, this slice offers a clear visual demonstration of how impact and thermal processes interact on airless bodies. Learn About Meteorites

Frequently asked questions

Is this meteorite authenticated? Yes. Sinawan 005 is classified in the Meteoritical Bulletin as Rumuruti (R5-6), found in Libya in 2023. You can verify the classification here: Sinawan 005. This specimen includes a certificate of authenticity from Treasure Coast Meteorite Co.

What does dual lithology mean in this context? Dual lithology refers to the presence of two distinct rock types within a single meteorite slice. In Sinawan 005, one zone shows type 5 metamorphism (partially recrystallized chondrules) while the adjacent zone exhibits type 6 metamorphism (nearly obliterated chondrules and coarser grain growth). The sharp boundary between them indicates they were brought together by impact rather than forming in place.

What is included with this specimen? You receive the 23.89g full slice shown in the photographs and a signed certificate of authenticity. No display stand is included unless separately listed.

Why are Rumuruti chondrites so rare? Rumuruti chondrites come from a single, unidentified parent asteroid that formed in a highly oxidizing region of the early solar system. Because they originate from one source rather than multiple parent bodies like ordinary chondrites, and because that source produces relatively few meteorite falls, Rumuruti specimens remain exceptionally scarce in collections worldwide.

How should this slice be displayed? The dual lithology boundary is the defining visual feature. Display the slice face-up under good lighting to emphasize the contrast between the light and dark zones. Side lighting will highlight the texture differences between the two metamorphic grades.

Collector significance

Sinawan 005 is one of only three known specimens of this R5-6 transitional type, placing it among the rarest chondrite classifications available to private collectors. The dual lithology character adds scientific interest beyond simple rarity -- this is not just a scarce meteorite type, but a specimen that actively demonstrates metamorphic processes and impact mixing within an asteroid. For collectors building representative type collections, Rumuruti chondrites are essential and difficult to acquire. A transitional grade with visible lithological variation is an opportunity to own a specimen that would be equally at home in a research collection.

At 23.89g, this slice is large enough to show both lithologies clearly while remaining accessible for private acquisition. The boundary between zones is sharp and well-preserved, making the dual character immediately apparent without magnification. This is a specimen that tells a story about asteroid interiors and impact processes, not just a catalog entry. Collectors focused on chondrite diversity will find few opportunities to acquire Rumuruti material at this size and visual clarity. Chondrites

Meteoritical Bulletin entry: Sinawan 005 | Classification: Rumuruti (R5-6) | Find, Libya, 2023