BH250-57
Title
BH250-57
Subject
Skarn Deposit
Description
Major Mineral: tourmaline
Minor Minerals: calcite (secondary), fluorite, muscovite, quartz
Mineralogy Comments: skarn deposit
BH250-57 represents a skarn deposit, typically formed by contact metamorphism and metasomatic alteration of carbonate rocks (limestone or dolomite) in the presence of an intruding magma.
Major mineral is tourmaline, zoned; many crystals are cut perpendicular to the c-axis, producing optic-axis-centered uniaxial negative interference figures. Other minerals such as calcite, fluorite, muscovite, quartz are also present.
Tourmaline is the dominant phase, suggesting boron-rich fluids during skarn formation.
Fluorite, muscovite, and quartz reflect complex hydrothermal fluid interactions, typical of skarn systems.
Minor Minerals: calcite (secondary), fluorite, muscovite, quartz
Mineralogy Comments: skarn deposit
BH250-57 represents a skarn deposit, typically formed by contact metamorphism and metasomatic alteration of carbonate rocks (limestone or dolomite) in the presence of an intruding magma.
Major mineral is tourmaline, zoned; many crystals are cut perpendicular to the c-axis, producing optic-axis-centered uniaxial negative interference figures. Other minerals such as calcite, fluorite, muscovite, quartz are also present.
Tourmaline is the dominant phase, suggesting boron-rich fluids during skarn formation.
Fluorite, muscovite, and quartz reflect complex hydrothermal fluid interactions, typical of skarn systems.
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-57. Housed at Carleton College in Minnesota.
Type
Thin section
Relation
View on ArcGIS Online here
Tourmaline interference figure
Tourmaline interference figure
Off-centered tourmaline interference figure
Collection
Citation
Bereket Haileab, “BH250-57,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/66.