10x lens for diamond inspection?

I've got one of these lens from my cousin (which is 20 years older than me) with a 10x zoom, LoL.

Now that I have a portable 10x lens, I will try to use it to observe lots of minute stuffs. When he handed me that lens, he let me try the lens on a few diamonds, to observe the clarity of them. Even though some impurities could be observed, they aren't visible to the naked eye. After all is said, they sure are shiny (and don't forgot that its extremely expensive), LoLoL~
Those diamonds costs a ton! I saw it ranges from MYR2,000 to MYR30,000!

Now that I have my own lens, I could also use it to observe mine...