louping like GIA

[30yearsofdiamonds]

For anyone looking at loose diamonds and given the opportunity to loupe the diamond. The photo shows the method used by GIA. Please notice the light source location and position of the stone in the tweezers, locking tweezers may help if available. Also notice the distance from diamond to the loupe and from the loupe to the eye. It is best to loupe the diamond in 4 rotations of 45 degrees so that the light enters the stone from different directions so that the grade setting inclusions are affected differently in each rotation.

 

[kenny]

Thank you for this.
I love learning techniques from experts.

Isn't dark-field better for getting inclusions to show up?
Does your pic demonstrate GIA's lighting for grading clarity?

Also I've heard it's good to find out which is your dominate eye and put the loupe in front of that one, while keeping both eyes open.
True?

 

[SandyinAnaheim]

I've heard it's good to find out which is your dominant eye and put the loupe in front of that one, while keeping both eyes open. True?

I've heard this as well. I see quite a bit better with one eye than the other. Interesting bit about the lighting...thanks.

 

[WinkHPD]

Kenny, the picture shows having the light from the lamp enter the diamond from the side which emulates the type of lighting that we get in a dark field microscope. Be sure to notice also that the hand is in contact with the face, providing a steady platform for the loupe, rather than tying to hold it steady without that contact which is impossible for most people. I suspect that if we could see from a different angle that you would also see the left hand braced against the right to also provide a steady platform for holding the diamond steady as well as the loupe. Keeping both eyes open is important as it helps to prevent the horrible headaches that will follow if you keep one eye closed and use the loupe for long.

While the loupe is a great tool that many of us in the trade use daily, if you are looking at diamonds in a store you might want to ask to see the diamond through the microscope. You will be able to see things immediately that it will take you years to learn to see through a loupe.

Of course, if the store will not let you use the microscope, or does not have one, then you might think of pulling a Forrest Gump and Run, Forrest, Run...

Wink

 

[30yearsofdiamonds]

That is correct, both hands are in contact with each other and the elbows are either on the table, or the forearms are braced against the edge of the table. Microscopes are definitely better, but in many stores look as if they are there for decoration.