very colorful multispectral mineral

[Fandyus]

Lately, I have been having much fun taking pictures of different objects in many bands and then combining the data I get in different ways. I have gotten many interesting results which I will share later but for now I would like to share images of this beautifully blue mineral I got on a flea market on saturday.

The images are in full hd.

 As I usually do,  I took several images of the rock in different bands. Three IR bands with my GRB3 method, a normal RGB image (as seen above), and a UV image with a ZWB2 and QB39.

 

950nm

 

850nm

 

720nm

 

red

 

green

 

blue

 

UV

 

Out of curiosity, I also did a UV picture with the same exposure time, aperture and ISO with a 510nm longpass filter screwed on top of the two filters. I think the result was very impressive considering this was a halogen spotlight and not even the sun or some other better lightsource.

This image was pushed by 8.612 stops in Darktable.

 

Now for the more artistic interpretations.

G-B-UV

 

950nm-850nm-720nm

 

Aerochrome simulation

 

850+720+R

 

full spectrum (850nm+950nm+720nm)-(R+G+B)-UV

 

Edit: here's a full spectrum stack made with a hybrid method I developed using advice from both @Stefano and @Andrea B. (found in this thread):

I think it looks much better.

 

(stackmode maxium)-(stackmode median)-(stackmode minimum)

 

stackmode range, normalized

Brighter areas show where the minaral is the least consistent in its reflectance. It's very inconsistent overall.

 

[colinbm]

I like seeing the deeper penetration of the IR light.

[Andrea B.]

Very interesting that the IR reflectivity increases so much after 850 nm. 

 

Anybody know what this mineral is? I thought for a sec that it was chalcedony, but it seems too dark for that.

Does this rock fluoresce?

 

 

[Alaun]

It looks like a geode.

[Fandyus]

On 8/16/2023 at 7:45 AM, Andrea B. said:

Very interesting that the IR reflectivity increases so much after 850 nm. 

 

Anybody know what this mineral is? I thought for a sec that it was chalcedony, but it seems too dark for that.

Does this rock fluoresce?

 

 

It fluoresces orange when hit with 365nm, but very faintly, and mostly the sides. I'd like to photograph it but I'm not sure I have any objects dark enough to get sufficient contrast and dust would be very annoying.