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Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
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 Posted: Nov 25, 2021 10:27 Post subject: Epitaxial or twinned rutile? |
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I have not photomicrography equipment but recently I bough a mobile phone with microscope camera (30x). Depth of field is very short, focal length is fixed and there is no possibility of stacking photos. Even so, some shots are useful to observe details.
I took some photos of the same rutile in last photo and also of another one on hematite. What I see leads me to think about the possibility that epitaxy and twinning coexist in some sagenite nets. Maybe this is a common thing but I haven't read about it.
Comments are welcome, thanks for your interest.
| Mineral: | Rutile |
| Locality: | | Alchuri, Shigar District, Gilgit-Baltistan (Northern Areas), Pakistan |  |
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| Dimensions: | FoV: 2.0 mm |
| Description: |
Contacts between needles are not perfectly encased elbows as we see in macro twins
Central diagonal needles are somewhat divergent, maybe one is epitactic and the other one twinned? |
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| Viewed: |
18171 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Alchuri, Shigar District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
| Unconnected needles form about 60º angles while some small elbows above left at the photo are ≈65º |
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| Viewed: |
18183 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Alchuri, Shigar District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
| Vertical and oblique rutile are connected forming ≈65º angles |
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| Viewed: |
18193 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Tormiq Valley, Baltistan District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
| Connected needles at the lower half of photo are at ≈65º while overlapped ones in the upper half form ≈60º anglesTwinning, epitaxy or both? |
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| Viewed: |
18176 Time(s) |
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| Mineral: | Rutile on hematite with muscovite |
| Locality: | | Alchuri, Shigar District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | 6 x 4.5 x 1.5 cm |
| Description: |
| Hematite with epitaxial rutile running perfectly parallel to its three crystallographic basal axes |
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| Viewed: |
18183 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Tormiq Valley, Baltistan District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.5 cm |
| Description: |
| Macroscopically, rutile runs parallel to crystallographic axes forming ≈60º angles… |
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| Viewed: |
18177 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Tormiq Valley, Baltistan District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
| …but microscopically most angles are ≈65º and elbows look like perfect twin joints |
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| Viewed: |
18181 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Tormiq Valley, Baltistan District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
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| Viewed: |
18188 Time(s) |
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| Mineral: | Rutile |
| Locality: | | Tormiq Valley, Baltistan District, Gilgit-Baltistan (Northern Areas), Pakistan | |
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| Dimensions: | FoV: 2.66 mm |
| Description: |
Even staggered neat elbows at ≈65º
Epitaxy, twinning or a combination? |
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| Viewed: |
18138 Time(s) |
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Eck Noch
Joined: 09 Jan 2021
Posts: 28
Location: California
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| Posted: Nov 25, 2021 11:57 Post subject: Re: Epitaxial rutile |
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Here is a fun one taken of my self collected material from the Eclipse Mine, photomicrograh by Nathan Renfro. Proposed epitaxy of rutile on Anatase or Brookite.
| Mineral: | Rutile |
| Locality: | | El Dorado County, California, USA | |
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| Dimensions: | 3mm |
| Description: |
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| Viewed: |
18123 Time(s) |
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Eck Noch
Joined: 09 Jan 2021
Posts: 28
Location: California
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| Posted: Nov 25, 2021 12:18 Post subject: Re: Epitaxial rutile |
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Here is a sample of photos I took myself with my iPhone 6, these were all collected from the Eclipse Pocket at our Eclipse Mine. Here you can clearly make out the Anatase cores on some, and on others it is not visible... there are easily 5 different colors of rutile that came from this pocket.
| Mineral: | Anatase, Rutile |
| Locality: | | El Dorado County, California, USA | |
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| Dimensions: | 8mm |
| Description: |
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| Viewed: |
18137 Time(s) |
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| Mineral: | Anatase, Rutile, Chlorite |
| Locality: | | El Dorado County, California, USA | |
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| Description: |
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| Viewed: |
18141 Time(s) |
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| Mineral: | Rutile |
| Locality: | | El Dorado County, California, USA | |
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| Dimensions: | 9mm |
| Description: |
| I love the blonde color of this Rutile. Also from the Eclipse Pocket at the Eclipse Mine. Unknown core mineral. |
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| Viewed: |
18111 Time(s) |
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| Mineral: | Anatase, Rutile, Dolomite |
| Locality: | | El Dorado County, California, USA | |
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| Dimensions: | 7mm |
| Description: |
| Two colors of rutile side by side. |
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| Viewed: |
18125 Time(s) |
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Eck Noch
Joined: 09 Jan 2021
Posts: 28
Location: California
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| Posted: Nov 25, 2021 12:33 Post subject: Re: Epitaxial rutile |
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Another photo micrograph by Nathan Renfro of material from the Eclipse Pocket.
| Mineral: | Rutile on Quartz |
| Locality: | | El Dorado County, California, USA | |
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| Description: |
| Photo Credit: Nathan Renfro |
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| Viewed: |
18127 Time(s) |
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Bob Morgan
Joined: 18 Jan 2018
Posts: 251
Location: Savannah, Georgia
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| Posted: Feb 27, 2022 18:28 Post subject: Re: Epitaxial rutile |
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If you want to explore rutile twinning there is an article that is above my pay grade:
Structural rationale for the occurrence of the elbow twins in cassiterite and rutile by Massimo Nespoli and Bernd Soignier in the Journal of Mineralogical and Petrological Sciences, Volume 110, pages 157-165, 2015.
It is theoretical and mathematical but has some interesting illustrations, and helps me appreciate that twinning is more complex than just simple twin planes.
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