Although I'll admit I thought it an odd response, and considered the possibility that it was somehow directed at me, I usually give people the benefit of the doubt and figured you didn't actually expect me to tell you something I don't believe is true just to protect your ego. So I wasn't offended in the least. I know learning to ID marbles is not an easy thing and can be frustrating as heck - I've been working on it for decades and I'm still often wrong. Just keep at it and keep it fun - after all, they're only marbles.