Images
Formula: Sn2+3O2(OH)2
Oxide containing hydroxyl, anthropogenic
Crystal System: Tetragonal
Specific gravity: 4.904 calculated
Streak: White
Colour: White
Environments
Hydromarchite generally is of anthropogenic origin by preferential leaching and oxidation of
tin from tin, bronze, or pewter artifacts in a marine or fluvial environment
(HOM).
Localities
At the type locality, Boundary Falls, Winnipeg River, Kenora District, Ontario, Canada, hydromarchite occurs
as an alteration product on pewter bowls dropped in the river between 1801 and 1821, and is a product of
tin corrosion in a unique cold freshwater environment, as is the associated mineral
romarchite. Type hydroromarchite forms euhedral single crystals.
Additional Sn-bearing corrosion products are cassiterite and two
unidentified phases
(CM 41.649-657, HOM).
At the Speranza Stope, Corchia mine, Berceto, Parma Province, Emilia-Romagna, Italy, hydromarchite is
interstitial in quartz-calcite
gangue of a massive
sphalerite-pyrite ore body.
Associated minerals include siderite,
pyrite, smithsonite,
sphalerite and baryte
(HOM).
The hydroromarchite occurs in massive
zinc-iron ore, closely related with late
deposition of siderite and
secondary pyrite,
possibly due to the action of neutral to basic and reducing waters flushing through the ore in the initial stages of
seafloor diagenesis
(CM 43.935-950).
At the Queen Anne's Revenge wreck site, Beaufort, Carteret county, North Carolina, USA, pewter plates and implements
have been recovered and examined from what is believed to be the flagship of the pirate Blackbeard, that sank in 1718.
All of the pewter artifacts from the site display a surface veneer of corrosion products composed of
romarchite, hydroromarchite and
abhurite. The corrosion generally develops in crudely concentric layers, with
an inner layer of abhurite in contact with the pewter, and overlying outer
layers of romarchite and hydroromarchite. All three minerals occur
as irregular grains and laths up to 100 micrometers in length
(CM 41.659-669).
Back to Minerals