Sphalerite : ZnS
Falcacci stope, Rio Mine, Rio Marina, Rio, Livorno Province, Tuscany, Italy

How to use the mindat.org media viewer

Click/touch this help panel to close it.

Welcome to the mindat.org media viewer. Here is a quick guide to some of the options available to you. Different controls are available depending on the type of media being shown (photo, video, animation, 3d image)

Controls - all media types

Zoom in and out of media using your mousewheel or with a two-finger 'resize' action on a touch device.

Use the mouse or your finger to drag the image or the view area of the image around the screen.

< and > at the left and right hand side of the screen move forwards and backwards for the other images associated with the media you selected. Usually this is used for previous/next photo in a gallery, in an article or in search results. Keyboard shortcuts: use shift + the left and right arrow keys.

< and > in the bottom center are used for switching between the photos of the same specimen. Keyboard shortcuts: use the left and right arrow keys.

> in the bottom center, raises the information box giving details and further options for the media, < at the top of this box then hides it. Keyboard shortcuts: use the up and down arrow keys.

? opens this help window. Keyboard shortcuts: use the H key or the ? key.

Other keyboard shortcuts:

1	Fit image to screen
2	Fill screen with image
5	Display at full resolution
<	Make background darker
>	Make background lighter
space	Hide/dim titles and buttons

Scalebar

If the field of view (FOV) is specified for the photo, the scalebar appears in the left bottom corner of the viewer. The scalebar is draggable and resizeable. Drag the right edge to resize it. Double click will reset the scalebar to it's default size and position. If the scalebar is in default position, double click will make it circular.

Controls - Video

Video files have a standard set of video controls: - Reset to start, - Skip back, - Play, - Pause, - Skip forwards. Keyboard shortcuts: You can stop/start video play with the P key.

Controls - Animation (Spin Rotation)

Animation (usually 360 degree spin rotations) have their own controls: - enable spin mode. Note that while images are loading this option will not be available but will be automatically activated when the animation has loaded. Once active you can spin the image/change the animation by moving your mouse or finger on the image left/right or by pressing the [ or ] keys.

The button switches to move mode so that you can use your mouse/fingers to move the image around the screen as with other media types.

The button, or the P key will start playing the animation directly, you can interrupt this by using the mouse or finger on the image to regain manual movement control.

Controls - 3D Stereoscopic images

If a stereoscopic 3D image is opened in the viewer, the 3D button appears in the bottom right corner giving access to "3D settings" menu. The 3D images can be viewed in several ways:
- without any special equipment using cross-eyed or parallel-eyed method
- with stereoscope
- with anaglyph glasses.
- on a suitable 3D TV or monitor (passive 3D system)

For details about 3D refer to: Mindat manuals: Mindat Media Viewer: 3D

To enable/disable 3D stereo display of a compatible stereo pair image press the 3 key. If the left/right images are reversed on your display (this often happens in full-screen mode) press the 4 key to reverse them.

Controls - photo comparison mode

If a photo with activated comparison mode is opened in the viewer, the button appears in the bottom right corner giving access to "Comparison mode settings" menu.

Several layouts are supported: slider and side by-side comparison with up to 6 photos shown synchronously on the screen. On each of the compared photos a view selector is placed, e.g.: Longwave UV ▼. It shows the name of currently selected view and allows to select a view for each placeholder.

Summary of all keyboard shortcuts

1	Fit image to screen
2	Fill screen with image
3	Switch to 3D display of stereo pair
4	Switch left/right images in 3D mode
5	Display at full resolution
<, >	Make background darker/lighter
H or ?	Show/hide this help page
P	Play/Pause Video or Animation
[, ]	Backwards/forwards one frame (Animation only)
space	Hide/dim titles and buttons
up arrow	Show information box
down arrow	Hide information box
left arrow	Previous child photo
right arrow	Next child photo
shift + left arrow	Previous image on the page
shift + right arrow	Next image on the page

minID: KQY-X75

Sphalerite : ZnS

This image is copyrighted. Unauthorized reproduction prohibited.

Locality: ⓘ Falcacci stope, Rio Mine, Rio Marina, Rio, Livorno Province, Tuscany, Italy

Dimensions: 3 mm x 3 mm x 3 mm

Typical habit of sphalerite crystal from Falcacci stope.
Cube (red).
Tetrahedra: direct (green) and inverse (blue).
Crystal size: 3 mm.
Collected in 1991, coll. & photo Giuliano Bettini.

This Photo was Mindat.org Photo of the Day - 30th May 2014

This photo has been shown 1167 times

Photo added:	2nd May 2014
Dimensions:	1953x1383px (2.70 megapixels)

Data Identifiers

Mindat Photo ID:	610721 📋 (quote this with any query about this photo)
Long-form Identifier:	mindat:1:4:610721:2 📋
GUID:	7c45ae82-cbce-4b89-9948-6efcdc3d50d7 📋
Specimen MinID	KQY-X75 (note: this is not unique to this photo, it is unique to the specimen)

View Giuliano Bettini's Photos View Sphalerite Gallery

Discuss this Photo

PhotosSphalerite - Falcacci stope, Rio Mine, Rio Marina, Elba Island, Livorno Province, Tuscany, Italy

30th May 2014 09:52 UTCJosé Zendrera 🌟 Manager

I think there is a mistake in this image description:

"Typical habit of sphalerite crystal from Falcacci stope.

Cube (red).

Tetrahedra: direct (green) and inverse (blue)."

To my understanding, green and blue faces belongs to octahedron, not to "direct" and "inverse" tetrahedrons.

30th May 2014 12:10 UTCGerhard Niklasch Expert

Sphalerite crystallizes in the hextetrahedral class. The positive and negative tetrahedron are separate, inequivalent forms.

A nice illustration for the ongoing International Year of Crystallography! :)-D

Cheers, Gerhard

30th May 2014 14:40 UTCReiner Mielke Expert

Very nice illustration! Thank you Giuliano! Just the kind of thing we need more of on Mindat.

30th May 2014 16:00 UTCJosé Zendrera 🌟 Manager

Oh, oh, it is clear that I have much to learn, thank you very much for explanations.

One more question: a combination of direct and inverse tetrahedrons will conform an ocahedron or only a bipyramide? I mean, angles between opposed faces measured across a vertice in an octahedron are equal to angles between faces measured perpendiculary to a edge in the tetrahedron?

Thanks again.

30th May 2014 19:36 UTCRob Woodside 🌟 Manager

A positive and negative tetrahedon in equal development give an octahedron. I used to be bothered when photos of sphalerite showing triangular faces were called Octos!!! I'd huff and puff about sphalerite being tetrahedral and not making octos. Then in short order I saw a perched octo from Naica and most Bulgarian sphalerites are also octos, which is much shorter than "positive and negative tetrahedrons in equal development"!

30th May 2014 21:37 UTCEd Clopton 🌟 Expert

Jose:

I'm operating at the very limit of my understanding of crystallography, but here goes: In crystallographic terms, an octahedron is a set of eight faces that occur together, and the crystal structure of the mineral must be such that all eight faces can form at once. Sphalerite does not have that degree of symmetry; the best it can do is a couple of tetrahedrons that may (in fact, usually do) occur one at a time depending on pressure, temperature, pH, trace elements, phase of the moon, and whatever else influences the decisions crystals make about which forms to develop.

If all the stars are properly aligned, both tetrahedron forms develop and the result is what looks to a geometrically oriented person like an octahedron--but a crystallographer recognizes it (especially if the faces are color-coded) as two equally developed tetrahedrons.

A similar thing happens with the terminal faces on quartz. Ordinary (alpha) quartz is terminated most often by two rhombohedron forms. Sometimes you see only one of them, resulting in a trigonal pyramid on top of the prism, and sometimes you see both equally developed, resulting in what looks like a hexagonal pyramid. Usually they are unequally developed, resulting in a termination with three large faces and three small faces. High-temperature beta quartz has true hexagonal symmetry, which produces a genuine six-sided pyramid, as opposed to alpha quartz's two intersecting forms that may coincidentally produce a pyramid-like form with six sides.

30th May 2014 22:09 UTCJosé Zendrera 🌟 Manager

Thank you Rob and Ed, now I understand. Is amazing (and to me a little confusing!) how some minerals can do forms belonging to a superior crystallographic class than his own class.

sphalerite {111}, {1-11}, {100}

Although here are also present positive and negative tetrahedrons plus the hexahedron, is not confusing due to different development of tetrahedrons.

image ©: smorf http://www.smorf.nl/crystals_az_naam.php?crystal=Sphalerite_009

5th Jun 2014 00:08 UTCJosé Zendrera 🌟 Manager

Today I was rereading an old book (Minerals from Spain, Calderon, 1910) and I meet this drawing that shows sphalerite twins:

If these forms are really twins now I understand why the picture which start this thread has a octahedral simetry, which would not be possible in a single crystal belonging to hexatetrahedral class.

Is this a twin as stated in this old book?

Thanks for your comments.

5th Jun 2014 00:25 UTCRob Woodside 🌟 Manager

Fig 10 is not a twin, but it seems that Fig. 11 is on 111. Notice that if you only saw a smooth pyrite cube, you would say it is hexoctahedral like fluorite or galena and miss the fact that it is in the pyritohedral class. If only a few simple forms develop, a crystal can mimic a higher symmetry class as in a pyrite cube or sphalerite octo.

5th Jun 2014 17:08 UTCJosé Zendrera 🌟 Manager

Thank you Rob, pyrite example is very clarifying to understand that some crystal forms have a superior simmetry than his theorical simmetry class.

Anyway this sphalerite with both regular and inverse tetrahedrons is still very baffling to me...

7th Jun 2014 21:19 UTCJosé Zendrera 🌟 Manager

Just to comment that in the book Mineralogy for amateurs (J. Sinkankas, 1964) in pag. 296 there is a figure similar to Fig. 10 viewed above and says: "Twinning very common on o<111>, and repeated, manifested by narrow striations and bands of slightly differing luster on crystal surfaces and cleavage planes."

Perhaps Calderon and Sinkankas they refers to a polisynthetic twinning?

7th Jun 2014 22:01 UTCUwe Kolitsch Manager

Yes, they do. The result can be some strange "hexagonal prisms" such as http://www.mindat.org/photo-21209.html.

8th Jun 2014 01:53 UTCRob Woodside 🌟 Manager

Thanks Uwe, without a x-ray most would think that wurtzite. Copper can make similar polysynthetic hexagonal prisms and there is no question there about some kind of pseudomorph. Years ago it was reported that the Wurtzite from Thomaston Dam in Connecticut had all pseudoed to sphalerite. I guess the polysynthetic twin lines here argue against any pseudomorphism here.

8th Jun 2014 11:12 UTCJosé Zendrera 🌟 Manager

Let me show what I think is another example of polysynthetic twinning in sphalerite. Unfortunately, in this case, the crystal faces are not appreciated.

Sphalerite

Las Manforas Mine (Aliva Mine), Camaleño, Cantabria, Spain

8,5 x 6 x 4,5 cm

Mineral and/or Locality

Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 26, 2024 00:43:57

Sphalerite : ZnSFalcacci stope, Rio Mine, Rio Marina, Rio, Livorno Province, Tuscany, Italy