Quartz : SiO2

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 for further 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:

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

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

Stereoscopic 3D image viewing requires a suitable 3D television or monitor correctly configured for your computer. Passive 3D systems such as LG 3DTVs are the easiest to configure for this.

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.

Summary of all keyboard shortcuts

1Fit image to screen
2Fill screen with image
3Switch to 3D display of stereo pair
4Switch left/right images in 3D mode
5Display at full resolution
<, >Make background darker/lighter
H or ?Show/hide this help page
PPlay/Pause Video or Animation
[, ]Backwards/forwards one frame (Animation only)
up arrowShow information box
down arrowHide information box
left arrowPrevious image/media page
right arrowNext image/media page
spaceHide/dim titles and buttons

Copyright © Amir C. Akhavan
minID: 9L6-ED1

Quartz : SiO2

Copyright © Amir C. Akhavan  - This image is copyrighted. Unauthorized reproduction prohibited.

Top view of a transparent smoky quartz crystal, 2.2 cm wide, from W Erongo Mountains, Namibia. Very likely from a miarole pocket and naturally etched by aggressive hot fluids. The strange looking pattern on its surface developed because r- and z- faces ({ 1 0 -1 1 } and { 0 1 -1 1 }) were effected by the fluids to a different degree. Because the crystal is a Dauphiné law twin, and Dauphiné law twins are penetration twins, each of the faces represents a mosaic of irregular twin domains that correspond to the r- and z-rhombohedral crystallographic forms, so it does not really make sense to talk of r- or z-faces on Dauphiné twins. There is no simple method to determine if the bright patches correspond to r- or z-forms.

You will note that each irregular patch has a straight border at the edge of a crystal face. The reason is not that the twin domain ends there - just the opposite - it continues on the neighboring crystal face: if the surface of a patch belonging to a certain twin domain corresponds to a z-form, the continuation of that patch must correspond to an r-form on an adjacent crystal face, and as a consequence one surface is etched, the other one not.
Bought from a street dealer at the Erongo in 2006.

This Photo was Mindat.org Photo of the Day - 28th Aug 2010

This photo has been shown 3948 times
Photo added:3rd Jul 2010
Dimensions:1024x1024px (1.05 megapixels)
View Amir C. Akhavan's Photos View Quartz Gallery
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