BH250-83b
Title
BH250-83b
Subject
Leucite
Description
Major Minerals: leucite, orthoclase, volcanic glass
Minor Minerals: mellite, augite, titanaugite, plagioclase
Optics: leucite with reaction rim, titanagute with strong anamalous interference colors.
Anomalous interference colors. Titanaugite contains significant titanium, which enhances pleochroic absorption. This strong absorption alters the way light travels through the crystal, leading to deviations from the normal interference colors expected from its birefringence. The anomalous interference colors observed in titanaugite are primarily caused by intense pleochroism and absorption related to its titanium and iron content a phenomenon known as anomalous interference coloration.
Texture: reaction rim, peritectic point, phase diagram, pseudo-isotropic, pseudoisotropic
Reaction rim: The observed texture (leucite with reaction rim) in this thin section formed through the reaction of leucite with silica, producing orthoclase:
Leucite (KAlSi₂O₆) + SiO₂ (melt) → Orthoclase (KAlSi₃O₈)
Minor Minerals: mellite, augite, titanaugite, plagioclase
Optics: leucite with reaction rim, titanagute with strong anamalous interference colors.
Anomalous interference colors. Titanaugite contains significant titanium, which enhances pleochroic absorption. This strong absorption alters the way light travels through the crystal, leading to deviations from the normal interference colors expected from its birefringence. The anomalous interference colors observed in titanaugite are primarily caused by intense pleochroism and absorption related to its titanium and iron content a phenomenon known as anomalous interference coloration.
Texture: reaction rim, peritectic point, phase diagram, pseudo-isotropic, pseudoisotropic
Reaction rim: The observed texture (leucite with reaction rim) in this thin section formed through the reaction of leucite with silica, producing orthoclase:
Leucite (KAlSi₂O₆) + SiO₂ (melt) → Orthoclase (KAlSi₃O₈)
Coverage
Location: Uganda
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-83b. Housed at Carleton College in Minnesota.
Contributor
Bereket Haielab
Frank H. Brown
Frank H. Brown
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-83b,” BH250 Mineralogy Teaching Collection, accessed April 26, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/94.