Mine, Stambaugh, Iron Co., Michigan, USA
5.9x 3.6 cm
by the standards of worldwide rhodochrosite, this piece leaves
something to be desired. What makes this piece stand out however, is
that it comes from Michigan, and it is particularly rich for the
is best known by mineral collectors for its coppers, however the
state was an important iron producer as well. In 1844
significant iron ore formations were discovered, and by 1890,
Michigan was responsible for 80% of US iron ore production.
This particular orebody was worked later on, from 1910 to 1963.
is interesting to note the matrix is actually rich iron ore-- it is
colored red by iron oxides, and has diffuse gray bands of other
minerals (presumably hematite) running through it.
Rhodochrosite is not an iron
mineral, but this site produced a number of manganese minerals in
addition to the iron ore- shigaite, manganite, and hausmanite to
name a few.
specimen is undoubtedly the result of collecting post-mining,
however it remains a rare (and pretty good) example from a classic
and historically important US mining district.