NWA 13790 - Winonaite (Primitive Achondrite)

NWA 13790 is a rare Winonaite, a type of Primitive Achondrite purchased after recovery from Northwest Africa in 2020. Winonaites represent transitional meteorite material, showing evidence of heating, recrystallisation, and partial melting on an early asteroid parent body without full separation into a typical core and mantle structure. With a reported total known weight of around 838 g, NWA 13790 is a relatively limited and scientifically interesting example of this uncommon meteorite group.

NWA 13790 specimens are described as coarse-grained mafic material containing olivine, low-calcium pyroxene, calcium-rich pyroxene, plagioclase feldspar, and iron-nickel metal. Some fragments retain fusion crust, while prepared pieces can show a mixture of silicate minerals and metallic phases. Its classification as a Winonaite is based on mineral chemistry and the abundance and form of the metal present, giving it a distinctive texture compared with more familiar Chondrites.

Studying NWA 13790 provides valuable insight into the intermediate stages between primitive Chondritic material and more fully differentiated Achondrites. Its limited recovered mass, Winonaite classification, and transitional nature make it especially appealing for collections focused on Primitive Achondrites, rare meteorite groups, or early asteroid evolution. Each specimen represents ancient solar system material that records an important stage in planetary processing.