Saw this spiral looking inclusion in a green colores gemstone that i havnt yet identified.id like help in identifying this inclusion.
Nirmala,
Your image taking skills are improving and growing! 
These are really good images! I believe the large inclusion is a partially healed step fracture, that could be called a feather type, but I haven’t found a reference inclusion. Still searching…
On another note, I have been away from my setup for the past few weeks, so I have not been able to collect and post images of the inclusions in a particular corundum gemstone, I mentioned earlier. So I apologize for the delay.
Cheers!
-Troy
Thank you troy…im so happy that you think im getting better in taking pictures.Actually i was using too high a magnification before .Now i realise that most inclusions can be seen in lower magnification.i still dont know the meaning of dark field lighting .Waiting for your pictures.Even ive been researching the inclusion .No luck till now.And in uv light its pinkish.
Nirmala,
Thanks for your patience with my delay in posting of photos. They are in the works now.
I do not know if you have seen this article on IGS regarding the microscope:
In there is a description of the different lighting methods and how they are applied. Dark field illumination is basically using an oblique angled light path to cross-illuminate the subject stone. It can sometimes (depending on model used) share the same apparatus for bright field illumination. This can also be accomplished with a home-brewed setup as well.
Here is an image of my microscope using a dark/bright field condenser.
I will post some images of the same stone/inclusion using the different light paths for comparison.