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Calcite


Calcite
Photo Information
Copyright: Joanna Wieczorek (cafecrem) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1201 W: 60 N: 1392] (9248)
Genre: Landscapes
Medium: Color
Date Taken: 2005-05
Camera: Olympus 740UZ
Photo Version: Original Version
Date Submitted: 2005-05-13 3:42
Viewed: 4067
Points: 32
[Note Guidelines] Photographer's Note
Next wonderful view from this fascinatig country - Romania!

The mineral calcite is a carbonate of calcium corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earth's surface. It is a common constituent of sedimentary rocks, limestone in particular. It is also the primary mineral in metamorphic marble. It also occurs as a vein mineral in deposits from hot springs, and also occurs in caverns as stalactites and stalagmites. Calcite is often the primary constituent of the shells of marine organisms (e.g. plankton, bivalves, etc.). Calcite represents the stable form of calcium carbonate; aragonite will change to calcite at 470°C.

Calcite crystals are hexagonal-rhombohedral, though actual calcite rhombohedrons are rare as natural crystals. However, they show a remarkable variety of habit including acute to obtuse rhombohedrons, tabular forms, prisms, or various scalenohedrons. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form. Its fracture is conchoidal, but difficult to obtain. It has a hardness of 3, a specific gravity of 2.7, and its luster is vitreous in crystallized varieties. Color is white or colorless, though shades of gray, red, yellow, green, blue, violet, brown, or even black can occur when the mineral is charged with impurities. Calcite reacts when it comes into contact with hydrochloric acid, which causes effervescence.


Doubly refracting calcite. The doubling is particularly obvious on the top bar of the letter T. The crystal is 1.5 inches long (4cm).Calcite is transparent to opaque and may occasionally show phosphorescence or fluorescence. It is perhaps best known because of its power to produce strong double refraction of light, such that objects viewed through a clear piece of calcite appear doubled in all of their parts - a phenomenon first described by Rasmus Bartholin. A beautifully transparent variety used for optical purposes comes from Iceland, called Iceland spar. Acute scalenohedral crystals are sometimes referred to as "dogtooth spar".
olar, dew77, red45, Janice, AndyB, coasties, TAZ, Comandante, liquidsunshine, nainnain has marked this note useful
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ThreadThread Starter Messages Updated
To Jancie: :-)cafecrem 2 05-13 06:53
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Critiques [Translate]

  • Great 
  • olar Gold Star Critiquer [C: 137 W: 0 N: 0] (0)
  • [2005-05-13 4:01]

Skaly i mineraly sa bardzo piekne zwłaszcza w naturze. Bardzo ciekawe zdjecie.

  • Great 
  • dew77 Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 4432 W: 248 N: 4028] (13270)
  • [2005-05-13 4:06]

Hello Joanna!
An unusual very nice shot.Lighting,composition and your note are perfect.TFS...:-)

  • Great 
  • red45 Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2636 W: 74 N: 9091] (31094)
  • [2005-05-13 4:13]

I remember all areas covered by calcite in our trip to Scarishoara cave. Very informative note completed by interesting picture. Looks like illustration from cookbook ;-)

Halo Joanna, interesting shot of the mineral calcite. Not as pretty as the snails, but I agree exactly with Olar's comments! And yes, Greg - this is like a beautiful iced cake. Well done.

  • Great 
  • AndyB Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 1366 W: 32 N: 1351] (3982)
  • [2005-05-13 5:00]

Hello Joanna,
This is a very nice capture.
Very good detail and textures with good lighting.
An interesting shot and note too.
Very well done.

witaj,
wspaniale:)podoba mi sie strasznie:) pokazane wysmienicie:) kolorki, dof wszystko ok:)

Nice composition Joanna. Lots of things to look at in this shot. I like the 'earthy' tones. Good light. Nice work. Thanks

Hello Joanna, Interesting shot - interesting notes. Thanx for "rocking" my world! ;-) Have a great weekend!!!

Nice shot, very well composed. Great details and colours.
Well done.
TFS.

  • Great 
  • sAner Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1455 W: 74 N: 1426] (4750)
  • [2005-05-13 18:22]

Hello Joanna,

A very nice picture. Sharp details, great DOF and very well exposed! I would have cropped the right side a bit more though. A very good photo though. TFS!

Regards,
Pieter

  • Great 
  • TAZ Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 2241 W: 47 N: 3167] (10926)
  • [2005-05-14 5:25]

Intéressante photographie pour ce minéral. Avec une note instructive.
Interesting & Well Done !

Very interresting shot!
Lighting,details and composition are excellent.
Thanks for sharing.

Nice shot Joanna,
well composed, good detail and colours,
Thanks for posting

  • Great 
  • ian Gold Star Critiquer [C: 65 W: 0 N: 0] (0)
  • [2005-05-17 5:21]

Hi Joanna!
Great photo. Wonderful colours. Pretty photo.

  • Great 
  • marjan Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 459 W: 14 N: 366] (2685)
  • [2005-11-29 12:06]

nice cristal of calcit.

salut JOHANA
bravo pour cette photo, je la trouve bien réussie et surtout ça change un peu
bonnes couleurs
j ai un peu le meme genre de photo mais n' osais pas les mettre pensant que cela n' avait rien de bon pour TN
bon week-end
edith

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