The monitor calibration tool will automatically calibrate your monitor. This depends on the quality of monitor and most monitors now have an excellent color gamut and should reproduce colors very well.
The data color monitor calibration tool:
You can buy a light tent for about 100 us dollars i think and it included natural daylight LEDs built into it so once you use the color checker you should have a way to automate and get very precise colors from your camera whether it’s a DSLR, a mirorless camera or s mobile phone as long as you put it through software that can use the camera profile you create for the specific camera and the light tent.
The color checker to build a camera profile:
Light tent:
Your total outlay would be about 300 USD for the tools, color checker and light tent. You would also pay about 10 USD a month for Lightroom to process the pictures. If you do this you will have a very high color fidelity that will allow you to get very consistent results with the gemeprice software.
Yes setting it up is a pain. Yes color correcting your monitor should be done at least once a week but preferably before color correcting your photos.
Yes it’s a hassle. But it’s a lot cheaper and more reliable than buying the book. The book will fade over time, especially if you use it under lots of light as the light will fade the white and any and all colors in the book.
I personally don’t see any better alternatives to doing this in order to get a very precise color grade for gemstones in general.
A mobile phone camera should be sufficient for this. If you want more precise color rendering i would suggest buying a Sony A6000 which can retail for about 300 USD or much less if you buy it used and a decent macro lens. A decent macro lens would be the 7artisand lens and that sells for about 100 USD. But like I said most mobile phone cameras should.be sufficient for this task so you don’t need to spend an additional 400 USD or more on camera gear.