On Offer: 41.7 gram amazing HED achondrite howardite meteorite with official name NWA 18047.

Official Name: NWA 18047 

Dimensions: 52.56 mm x 28.51 mm x26.85

Type: HED Howardite

Description: 41.7 gram HED howardite polymict breccia fragment with beautiful crust on two sides. Most meteorites classified as "howardite" are heavily brecciated with evidence of a high energy impact ejection event large enough to excavate material deep into the parent body's lower crust or upper mantle where the diogenitic components of the breccia are thought to be formed and exist. These high energy impact events are evidenced in this specimen by the existence of the diapplectic glass "maskelynite", which is a mineral glass created from plagioclase that has been transformed by intense impact shock waves. Olivine was not reported as a constituent in the analysis sample used for the classification of this polymict breccia. While some examples of this classification do have olivine present, this specimen does not appear to have any visible olivine. An exceptional feature of this meteorite specimen is that it displays well preserved black fusion crust with beautiful flow lines.   

The HED Meteorite Clan: petrological evidence and data from NASA's Dawn mission indicate that nearly monomineralic ultramafic orthopyroxenite, olivine-bearing, and the much more rare harzburgitic, and dunite diogenites formed alongside each other. They likely originated as cumulates within localized magma chambers (plutons) situated across Vesta's lower crust and the lower-crust/upper-mantle transition zone. While the eucrites represent more evolved plagioclase rich mafic upper to middle zone crustal material. The howardites were formed by impact mixing of the diogenitic and eucritic material both in situ and during ejection events.

The HED meteorites are so named for the three types of meteorites that comprise the group; Howardite, Eucrite and Diogenite. The Eucrite and Diogenite are meteorites with distinct chemistries, while the Howardite is a mix of the eucritic and diogenitic material. The HEDs are differentiated achondritic meteorites, thought to originate from the large differentiated asteroid 4 Vesta. Vesta is one of the only asteroids visible with the naked eye and low powered telescopes.

The Vesta parent body origin for the HED clan of meteorites is considered to have been conclusively established for many years. However, the late Dr. John Wasson, a planetary science researcher from UCLA had long held that the HED meteorite clan originated from another unknown Vesta-like asteroid that was blown apart long ago. This is because we also find a class of iron meteorites with nearly identical oxygen isotopes as the HED clan. This along with other research lead Dr. Wasson to conclude the HED clan of meteorites come from another differentiated V-type asteroid that was in a cataclysmic collision liberating part or all of its metal core along with the HED meteorites.

However, this hypothesis does not necessarily rule out the possibility that a "reaccreted" Vesta and the smaller V-type asteroids collectively known as Vestoids along with the HED meteorites and the isotopically paired irons were all once part of a much larger dwarf planet prior to a massive collision with another large body. While most researchers consider the case mostly closed on this debate, the paradox of isotopically paired core metal raised by Dr. Wasson's hypothesis has not been resolved. This leaves some to speculate that perhaps we still have more to learn about this fascinating clan of achondrite meteorites and even Vesta itself.

What you get: 41.7g Howardite meteorite specimen as shown, shipping/storage membrane box & signed Certificate of Authenticity.

We offer a 100% no questions asked 30 day return policy.