September 1957: a letter with an illegible signature reached O Globo columnist Ibrahim Sued, enclosing three lumps of grey metal said to be fragments of a disc that exploded at noon over a beach near Ubatuba, São Paulo. Rio physician Olavo Fontes collected them for APRO; a Brazilian government laboratory reported magnesium with “absence of any other metallic element”, and the founding claim was born: metal purer than 1957 technology could make.
The fragments became the only UAP artefact with a continuous laboratory record, 1957-2018. The purity claim died on that record: Oak Ridge read 99.8% (1958), Dow 99.98% (1961), and the Condon study’s neutron activation 99.88% (1968), all below Dow’s off-the-shelf triply sublimed magnesium at 99.998%. Condon’s verdict: “The claim of unusual purity of the magnesium fragments has been disproved.” The same 1968 laboratory produced a bungled isotope estimate (²⁶Mg at 14.3%) that was omitted from the published report and surfaced from Craig’s papers only in 2008; no later laboratory ever reproduced it. Every isotope analysis with stated precision, from the Wasserburg laboratory at Caltech (1976) to ICP-MS in Cleveland (2018), put the fragments on the terrestrial mass-dependent fractionation line, where a genuine ²⁶Al relic would sit tens of permil off it.
Two facts keep the file interesting. The strontium: 500 ppm, uniformly alloyed, not a production contaminant, in Dow’s judgment intentionally added; Dow itself had poured a 700-gram experimental Mg-Sr batch at nominally this concentration in March 1940, but no batch was ever matched to the fragments. And the custody: two 1957 pieces vanished into Brazilian military laboratories, the USAF burned its sample in an arc spectrograph, one piece walked out of MIT with a visitor in 1984, and Sturrock, who inherited the collection in 1987, recorded that the association of the surviving specimens with the original three samples “had been completely lost.”
The station’s instrument INST-63 builds the measuring machinery: a magnetic-sector spectrometer at true scale, the three-isotope fractionation line, and a ledger that prices every claim at its detection limit.