Text and photos by Harold “Fritz” Moritz
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Amphiboles are important and widespread rock-forming minerals in the metamorphic rocks of
the highlands of Connecticut. Most of their specific characterization has been documented via
optical microscopy using thin-sections and published in bedrock geological quadrangle reports
since the 1950s. In less common instances, they can be found as large, distinct and collectible
crystals begging for detailed characterization. To date, most local amphiboles are identified as
tremolite (white to colorless), actinolite (green), hornblende (very dark green to black), or
anthophyllite (brown to green-brown in the Middletown Formation). The International
Mineralogical Association’s (IMA) many changes in nomenclature post-date most of the
literature about them in this state and so many more recognized species potentially exist based on
IMA’s subdivisions of earlier ones. To remedy this situation, during August 2016 and March
2017, I submitted samples of Connecticut amphiboles (or suspected ones) to Frank Craig for
TEM-EDS analyses. Frank is preparing an atlas of amphiboles and I am interested in
determining the various species found in Connecticut.
the highlands of Connecticut. Most of their specific characterization has been documented via
optical microscopy using thin-sections and published in bedrock geological quadrangle reports
since the 1950s. In less common instances, they can be found as large, distinct and collectible
crystals begging for detailed characterization. To date, most local amphiboles are identified as
tremolite (white to colorless), actinolite (green), hornblende (very dark green to black), or
anthophyllite (brown to green-brown in the Middletown Formation). The International
Mineralogical Association’s (IMA) many changes in nomenclature post-date most of the
literature about them in this state and so many more recognized species potentially exist based on
IMA’s subdivisions of earlier ones. To remedy this situation, during August 2016 and March
2017, I submitted samples of Connecticut amphiboles (or suspected ones) to Frank Craig for
TEM-EDS analyses. Frank is preparing an atlas of amphiboles and I am interested in
determining the various species found in Connecticut.