iPhone. For comparison, I have a Nikon Coolpix 3200 from 2003, Nikon Coolpix 4100 from 2005, and a Canon Elph from about 2005, and have tried macro settings. These are all digital point and shoot cameras.
The iPhone is hands down the most accurate, and actually captures red. It works best on an overcast or cloudy but bright day (diffused natural light). In general, diffused outdoor light, or diffused indoor light works best. Direct light flooding a stone, whether it be bright sunlight on a cloudless day, or a lamp light, causes glare, shadowing, and artificially lightened color.
Nope, doesn't help me, as I don't have an iPhone. I assume I'll be able to take good photos once I master the proper settings, so just asking for help that way. Kenny, unfortunately, there were a number of problems so I could not take photos. The main one was that it wasn't focusing and was registering as too dark - clearly I need to play around with settings a bit more, which means brushing up on the manual. I'm lazy. I was hoping someone could read my mind and come up with the answer for me...
Preg: thanks for the encouragement. I find that in the cold light of day, despite reading the manual for a good hour last night, I would rather be here posting than trying to figure out what I need to do to make it work. I'll hopefully screw up the determination in a bit, but right now, I am procrastinating.