Beautiful Achondrite, howardite with black crust and incusion of eucrite.
Vesta, NWA 10906 - 6,62g
2016, North West Africa
Registered by M.Bilet and classified by Carl Agee, University of New Mexico, USA.
Meteorites with the name HED stand for Howardite, Eucerite and Diogenite. These three acondrites show by spectroscopic examinations that they most likely come from the asteroid Vesta and are called "Vesta meteorites".
Howardites have a brittle (breccia) mixture of eucrites and diogenites. They originate from the upper layer of a planet and all indications are that they must have originated relatively close to the sun (possibly as close as the Earth). Eucrites are the most common acondrites and are very similar to the terrestrial rock. They have small crystals that are caused by rapid cooling of magma. Eucrites are rich in calcium, with plagioclase feldspar. The most obvious character of fresh eucrites is a very shiny (and black) burning membrane due to calcium and iron. Diogenites are named after the Greek philosopher Diogenes, who was the first to venture the claim that meteorites came from the sky. They contain large crystals of the magnesium- and iron-rich pyroxene minerals hypersten and bronzite. Due to their high iron content, they are darker than aubrits. Diogenites have a dull gray-black surface (burning membrane). Meteorites with the designation HED stand for Howardite, Eucerite and Diogenite. These three acondrites show by spectroscopic examinations that they most likely come from the asteroid Vesta and are called "Vesta meteorites".