Aragonite Crystal cluster

beetleman · Post by **beetleman** » Mon Mar 26, 2007 10:20 am

Just a cluster of Aragonite crystals. Specimen is about 1.5" wide. More info: http://geology.about.com/library/bl/ima ... gonite.htm

Ex. 1/2.5
F/8
ISO 100

Moebius · Post by **Moebius** » Mon Mar 26, 2007 12:16 pm

Nice pic Doug. Gotta say, looks crystal clear to me.

Ken Nelson

Bruce Williams · Post by **Bruce Williams** » Mon Mar 26, 2007 3:06 pm

A very professional looking study Doug. I'm guessing that with the the excellent front-to-back sharpness, at 1.5 inches there was some stacking involved? Your specimen makes a nice balanced composition too.

With these crystals (or crystals in general) is there an easily identified top and bottom. Could you tell for example how this cluster was oriented with respect to gravitational pull?

Textbook quality!

Bruce

MacroLuv · Post by **MacroLuv** » Mon Mar 26, 2007 3:13 pm

Very nice and allover sharp.

Must be stacked.

beetleman · Post by **beetleman** » Tue Mar 27, 2007 5:46 am

Well, what I did was I took some pictures with different F stops and then I took two stacks and I just liked the way the non stacked picture came out. Here is one of the stacked shots (5 photo stack). I thought they were a little hot so I did not use it. The stack shot is a little closer.

Bruce, there is a section on the bottom of this crystal group that suggest it was attached to something else...as for oriented with respect to gravitational pull?

Stacked photo: 5 photo stack Some sharpening applied

microcollector · Post by **microcollector** » Tue Mar 27, 2007 9:29 pm

Bruce

aragonite crystallizes in the orthorhombic system. While these crystals appear hexagonal when looking down the c axis, this is caused by twinning. The flat ends of the crystals would be considered the top or bottom. This is the c face. The three crystal axes in the orthorhombic system are at right angles to each other and are differnet lenghts. Crystallography can be very interesting and frustrating as nature seldom produces textbook examples.

Doug Merson