Post by LCARS on Oct 21, 2007 2:47:11 GMT -5
Well, I have been avoiding posting a pic of this cabochon that I cut from a small slab I picked up at the last rock show here.
The reason I have been avoiding posting a pic is because a mere picture simply can not show the effect of this strange material.
It is definately some type of obsidian, I can tell from the way it sounds when I tap on the slab and by the clean shiney break cleavage. The strange thing is that this particular obsidian has a unique type of chatoyance effect simillar to that fancy liquid soap where it reflects some of the light back at an angle that is non-incident with the light source but more in a flat swirl sort of pattern and only on a narrow plane.
Well, it is difficult to describe, which is why I tried my idea of placing this cab on a turntable and taking a series of over 40 photos at 4º increments with the remote shooting mode and then I created a motion video from the still frames. This did take a while but I think I have figured out a few shortcuts for next time.
Photobucket degraded the video a fair bit when it converted the format for uploading so if anyone is really interested in seeing a hi-res version I guess I can email the original (337kb) WMV video file that has about twice the resolution as the PB vid... unless i can upload it complete somewhere else that's publically accessible.
So, without further adue, here it is in 4-dimensions!
(click for vid)
The cab measures 13.75mm wide at the base, 16.75mm tall and 5.25mm at it's thickest. It has an inset neodymium magnet epoxied to it's back giving a mere +0.75mm profile.
I stuck a small sphere magnet to it for some back support during the photo session in case anyone was wondering what that is.
I'm going to try and refine my technique and do some more 4-dimensional cabs as time permits. it's a fair amount of work to do a sequence like this and I don't have a motorized turnatable that would allow me to take motion video instead but IMO, the hi-res video still images are just as good as if not better than camcorder footage at showing the transition of the effect.
Thanks for looking & your comments are all appreciated!
Rob
The reason I have been avoiding posting a pic is because a mere picture simply can not show the effect of this strange material.
It is definately some type of obsidian, I can tell from the way it sounds when I tap on the slab and by the clean shiney break cleavage. The strange thing is that this particular obsidian has a unique type of chatoyance effect simillar to that fancy liquid soap where it reflects some of the light back at an angle that is non-incident with the light source but more in a flat swirl sort of pattern and only on a narrow plane.
Well, it is difficult to describe, which is why I tried my idea of placing this cab on a turntable and taking a series of over 40 photos at 4º increments with the remote shooting mode and then I created a motion video from the still frames. This did take a while but I think I have figured out a few shortcuts for next time.
Photobucket degraded the video a fair bit when it converted the format for uploading so if anyone is really interested in seeing a hi-res version I guess I can email the original (337kb) WMV video file that has about twice the resolution as the PB vid... unless i can upload it complete somewhere else that's publically accessible.
So, without further adue, here it is in 4-dimensions!
(click for vid)
The cab measures 13.75mm wide at the base, 16.75mm tall and 5.25mm at it's thickest. It has an inset neodymium magnet epoxied to it's back giving a mere +0.75mm profile.
I stuck a small sphere magnet to it for some back support during the photo session in case anyone was wondering what that is.
I'm going to try and refine my technique and do some more 4-dimensional cabs as time permits. it's a fair amount of work to do a sequence like this and I don't have a motorized turnatable that would allow me to take motion video instead but IMO, the hi-res video still images are just as good as if not better than camcorder footage at showing the transition of the effect.
Thanks for looking & your comments are all appreciated!
Rob
