My camera is a Nikon Coolpix. I hate I-phones.iPhone?
Get pro camera app. Turn white balance up to 10k. Take a video. You can screenshot the best focus from the video. It's hard to get snap shots with the iPhone for details.
If you have acrylic laying around or thin glass you can make a portal to get closer to it, or gently bring it to the surface if it's not affixed.