Bright green
Chromium substitution gives muscovite its distinctive green appearance.
THOR IN 3D · ALTERATION VECTOR
Fuchsite.A bright-green marker
of fluid–rock interaction.
Chromium-rich muscovite occurs locally within the Silver Cup District and in THOR-246. Its color makes it easy to recognize; its setting can help map structurally focused hydrothermal pathways.
- Mineral
- Cr-rich mica
- Visual cue
- Bright green
- Primary role
- Vector
- Ore mineral
- No
01 · MINERAL IDENTITY
A subtle alteration mineral with a conspicuous color.
Fuchsite is a chromium-bearing variety of muscovite. At Thor it occurs as localized green streaks and spots in altered rock, including carbonate-rich material around quartz–carbonate veins.
Visible alteration
Green mica within pale altered rock.
Bright green to blue-green mica occurs along the rock fabric and in localized patches, providing a recognizable field and core-logging cue.
02 · CORE EXPRESSION
Ocelli beside a quartz–carbonate vein.
THOR-246 contains dark-green fuchsite in carbonate-rich sediment beside a pale quartz–carbonate vein. The texture links the mineral to localized alteration rather than a continuous rock unit.
Streaks and spots
Fuchsite may follow the fabric, occur in small “eyes,” or concentrate beside veins.
Altered sediment
The Thor examples occur in carbonate-rich metasedimentary material.
Veins and contacts
Its occurrence records focused fluid interaction along permeable structures.
THOR-246
Vein, carbonate and fuchsite.
A pale vein occupies one side of the sample while green fuchsite occurs through the adjacent altered sediment.
03 · FORMATION SETTING
Chromium, aluminium and permeability converge.
Fuchsite formation requires the right chemistry and a pathway for fluid–rock exchange. The Silver Cup District combines reactive metasediments with folds, faults and shears capable of concentrating hydrothermal flow.
Reactive host rock
Metamorphosed pelitic or quartz-rich sediment can provide aluminium-bearing minerals for replacement.
Chromium-bearing system
Chromium must be present in the rock or mobilized by hydrothermal fluid to produce green muscovite.
Open pathways
Shears, fold hinges, faults and vein margins increase permeability and focus repeated fluid movement.
Why the Silver Cup architecture fits.
The Broadview and Sharon Creek metasedimentary packages are strongly deformed around the Silver Cup Anticline and cut by numerous faults and fractures. That combination creates the structural and lithological conditions in which localized fuchsite can form.
04 · VECTORING VALUE
A guide to structure—not a mineralized endpoint.
Fuchsite can help identify places where fluid pathways, reactive rocks and repeated alteration overlap. It is most useful when integrated with veins, assays, structure and geophysics.
Anticline limbs
Deformation along the Silver Cup Anticline may produce permeable, chemically reactive corridors.
Fault and shear intersections
Crossing structures can channel multiple fluid pulses and create focused alteration.
Quartz-vein margins
Green mica beside veins may record chromium-bearing fluid interaction with aluminium-rich host rock.
Covered structural panels
Core occurrences can help extend interpretation beneath rockslides or into incompletely tested areas.
05 · SYSTEM CONTEXT
Alteration interpreted within a multi-stage intrusive system.
The source page places fuchsite alongside the broader I-1 and lamprophyre framework. These contextual images are not photographs of fuchsite; they show the interpreted system and a separate porphyritic intrusive texture.
System context · not fuchsite
I-1 and the intrusive framework.
The model situates late alteration observations within the deeper architecture developed across the preceding atlas chapters.
Texture reference · not fuchsite
Porphyritic intrusive material.
This reused source image provides intrusive context. Its pale crystals should not be confused with the bright-green mica shown elsewhere on this page.
The strongest fuchsite interpretation comes from the green mineral’s own texture, mineral chemistry and structural setting. System-scale correlations remain hypotheses to test against mapping, petrography, geochemistry and drilling.