I'm not sure its gemstones you are thinking about.

If you go to the special horses page you can scroll through and will see that all those that do give a gift need to be worked each day.

Agate changes to a pass button but the others don't. Amber, Jade, Ruby, and Gypsum are on waking. Pearl with a mission. Opal is a carrot. Quartz is water. Amethyst gives a UFO after bedding. Onyx gives a UFO after grooming. Sapphire you follow to another players page the first time you visit them every day.

Oh yes. I must have missed agate. Do we know if the button does change if he hasn't been worked? I wok all mine anyway so can't tell

All gems need bedded after you visit their page if they're going to give passes.

ok so agate is the one that gets mash daily and is the only one where the button needed will change to an image of passes. I was curious cause I kept giving him mashes everyday and didn't wanna waste mashes/carrots/etc unless it was necessary.
I just need to remember cause I'm struggling trying to remember what needs what. I used to have this down to a T LOLL
Thanks mischief!

I used to check their special tab daily for the description, because that states what you need to do with each.

If you're a VIP/Pegasus, you can also write "carrot", "drink" , etc. in the horse's private notebook with the corresponding divine to help you remember. That's what I do.