A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 μm olivine feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated mantle of an asteroid, and appear to have a high density. One survey found that 7 similar A-, V- and X-type asteroids had an average density of 3.6 g/cm3.[1]