BH250-48
Title
BH250-48
Subject
Gneiss
Description
Major Mineral: Allanite
Other Major Minerals: Microcline, orthoclase, biotite, quartz, perthite
Mineralogical Comments:
Very large allanite crystals are present and show significant alteration. Myrmekite is common in association with feldspars.
Alteration:
Allanite is extensively altered, displaying patchy zoning, partial replacement rims, and loss of interference colors. Signs of metamictization and radiation damage are evident, including pleochroic halos around radioactive inclusions.
Other Major Minerals: Microcline, orthoclase, biotite, quartz, perthite
Mineralogical Comments:
Very large allanite crystals are present and show significant alteration. Myrmekite is common in association with feldspars.
Alteration:
Allanite is extensively altered, displaying patchy zoning, partial replacement rims, and loss of interference colors. Signs of metamictization and radiation damage are evident, including pleochroic halos around radioactive inclusions.
Coverage
Location: Beartooth Mountains, Wyoming, USA
GPS Coordinates: 44°55'38.67"N, 109°43'37.45"W
Nearby Geography: Beartooth Mountains
Collected during petrology field trip in 2000
GPS Coordinates: 44°55'38.67"N, 109°43'37.45"W
Nearby Geography: Beartooth Mountains
Collected during petrology field trip in 2000
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-48. Housed at Carleton College in Minnesota.
Contributor
Bereket Haileab
Type
Thin section and hand sample
Relation
Collection
Citation
Bereket Haileab, “BH250-48,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/55.