What is the "bisque" or "biscuit" color, and is it yellow-ish?
The bisque/biscuit color is simply an off-white. It is very neutral and does not look yellow at all. If you have dark cabinets or other off-white elements (tiles, appliances, cabinets, etc.), you may consider opting for the bisque/biscuit color.
My ring left a mark on my sink, did I scratch it!?
No, you did not scratch it. In most cases, your fireclay sink is going to be much harder than metal and the marks left are essentially your sink scratching the metal! Drag your fingernail across the mark and see if you can feel a groove. In 99% of cases, you will be able to buff it out with a cleaner and some elbow grease. If you did leave a scratch, you can fill it with a fireclay filler.