This pen has my favourite tortoiseshell pattern. It is a greenish transparent with brown veins. I cheated a bit with this combination as I want to ink up another of my Richard Binder grinds to take to Sydney.
A M250 14K single tone gold nib in extra fine, then Mr Binder trimmed the shoulders of this nib back and skimmed it to thin it slightly. All in an effort to make a nib that will flex, not wet noodle flex but springy flex. I don't tend to push this nib too hard.
Diamine Teal - which I classify as a blue-black, sheens red and shades lovely from this flexible fine nib. You can see where I gave it a bit more pressure on the downstroke.