Image from (CM 59.3.617–627)
Specific gravity: 3.68 measured and 3.69 calculated
Hardness: About 5
Streak: Pale green-yellow
Colour: Deep green-brown
Ferrobobfergusonite is a relatively new mineral, approved in 2017, and to date (March 2022) reported only from
the type locality.
At the type locality, the Victory Mine, Custer, Custer Mining District, Custer county, South Dakota, USA, ferrobobfergusonite has been found associated with ferrowyllieite, schorl, fillowite, arrojadite, quartz and muscovite. Broken pieces of massive ferrobobfergusonite are blocky or tabular with single crystals up to 0.9 × 0.7 × 0.4 mm (CM 59.3.617–627).
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