Gadolinium is one of the lanthanide elements. It is quite reactive and quickly is attacked by moisture and oxygen from the air. For this reason, the sample is ampouled in a tube, filled with argon. This sample of fine filings has a purity of 99.9%. The size of the sample shown here is 3 grams, each filing has a length of just 1 mm and a width of at most 0.5 mm. The filings are quite dark, this is because they are somewhat oxidized, before they were ampouled.