This reliquary-ark, in the shape of a rectangular coffin and of harmonious proportions, is topped by a lid of pyramidal body truncated at the top. Two indistinct figures of angels, in chiselled silver, flank the piece with open wings; it is still elegantly decorated by other angels of smaller dimensions. The base sits on four feet in chiselled silver, topped by cherubim. On the front of the base the coat of arms of King Pedro II stands out, enamelled and surrounded by golden spirals which at the time, could have formed a royal crown. The front of the main body has six oval medallions decorated in glass, lined with silk material, decorated with golden floral motifs.
The lateral faces of the lid present bands of friezes in silver with meticulous low relief, representing scenes of the martyrdom of Saint John de Brito in Orbyur, India, 1663. On top of the lid a wider low relief stands out with the representation of the indistinct figure of the missionary saint in his normal iconography: Indian tunic, head covered with a sari, sandals with wooden soles and a shepherd's crook. The presence of Agnus Dei topping the piece, surrounded by seraphim, could have been added later, under Jesuit initiative, bearing in mind the Eucharist function which was attributed to the ark.