Calcite : CaCO3, Fluorite : CaF2, Gonnardite : (Na,Ca)2(Si,Al)5O10·3H2O
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 |
This is a comparison of MW UV fluorescence and visible light images using the Mindat comparison tool. Under SW UV, only the bluish-white gonnardite glows significantly.
I found this on my first trip to MSH. At the time, I couldn’t tell one MSH mineral from another. It’s an ugly little thing that I probably kept because, in daylight, it’s such a mess that there must be something good on it – right? Eventually I figured out that the specimen host gonnardite (dull bluish-white in the UV image) and fluorite (bright blue). But neither of these is in any way remarkable for MSH, so the specimen languished in one of my reject boxes. But under MW UV it suddenly becomes quite interesting. Not only is there “flaming” calcite, which looks like a run-away grass fire, but there are a couple fluorescent UKs. One of these can be seen glowing yellowish in the lower left corner. The responses (both SW and MW) are somewhat similar to those of polylithionite, but the stuff doesn’t really look micaceous under a scope and it does not fall apart into thin flakes when poked with a needle. The other UK consists of elongated prisms that fluoresce weak to moderate green. There are several such minerals at MSH, but these prisms don’t look like any of them.
Update: When I went to photograph the UK green fluorescent “prisms”, it became evident that the “prisms” are the unbroken edges of rather dingy crystals of catapleiite. They look like prisms under UV because, for the most part, the actual tabular bodies of the crystals barely show up. See [https://www.mindat.org/photo-1336483.html]. I also realized that I had already previously posted a photo of some of the other fluorite on this specimen: [https://www.mindat.org/photo-1242392.html].
Note: Some of the calcite appears to be fluorescing bright orange or even yellow rather than red, and, at high magnofication, some cross-sections appear to be hexagonal. This led me to suspect that the stuff might be fluorapatite rather than calcite or an inter-growth of the two species. However, several samples dunked in HCl all fizzed vigorously and the "flaming red" response vanished in less than a minute. Because of the small size of the crystals, it is nearly impossible to get a pure sample consisting of just the red fluorescent stuff, so there is almost always a residue, sometimes consisting of tiny acicular crystals. But these don't fluoresce, so it isn't likely that they are fluorapatite. Also, a few small fragments which appeared to consist of the red fluorescent material only did fizz and vanished completely with no residue at all. So - despite the somewhat unusual UV response, the "flaming" stuff is probably all calcite.
The MW responses of the calcite and fluorite are very bright. Even though this is essentially just an oversized micro, the MW response looks about as bright as depicted with a 5 W LED flashlight held as far as 70-80 cm from the specimen. (Of course to see any details you need a scope.)
Collected: 1994
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