This Muonionalusta meteorite slice is from Muonionalustra in the Pajala District, Norrbotten County, Sweden. It was found in 1906 and is estimated to have fallen 1 million years ago. It is possibly the oldest meteorite known at 4.5653+/- 0.0001 billion years old. It is classified as an Iron Octahedrite Type IVA (Of). This piece was sliced and acid etched to reveal the prominent Widmanstatten patterns present inside the meteorite. This slice measures 79 x 79 x 1 mm thick. It weighs 72 grams.