Curious about the claimed powers of crystals...science or myth?

My wife has been collecting some beautiful crystals for a few years now. I enjoy looking at them; and I sometimes will hold some while repeating affirmations in hopes that I am increasing the power of my intentions. But I really don't know.

When we visit the stores where the crystals are sold, there are often little cards with claims of what the stones do for the possessor. But honestly it sounds a bit hyperbolic and fantastical. Is there any real science or metaphysical capabilities behind these legends? I do an online search and get so many pages like this: https://meanings.crystalsandjewelry.com/a-to-z-list-of-crystal-meanings/

I'm sorry, but claims made with no backing information won't make a believer of me. Learning some of the aspects of quantum physics really opened me up to much of my spirituality because it explains scientifically how things perceived as 'magic' can happen in our universe and how consciousness has an effect on our universe through the matrix/field.

Please educate me.

The information on their energetic workings are not there to convince anyone. They information, nothing more, nothing less.
The believing is more intuition, trusting your intuition, and feeling. That is an internal thing. Many find it easier to trust external things, like scientific proof and facts. But with energywork it isn't about that. It's about trusting yourself, listening to your intuition and surrendering to that. Not needing to know the science behind it (anymore). Science can be a nice confirmation but the best gauge is your own body, your intuition. But in order to benefit from that you have to tune into it, learn to listen to it.

Also sitting with a crystal and affirming sounds like you're trying to hard?
Affirming can be helpful, but it doesn't have to be.
What you affirm must be the same or very close to what you already believe & feel otherwise it has the opposite effect.
For instance if you don't feel happy at all and start affirming "I am happy! Life is good. I am happy!" you're creating a gap between you and you: the conscious you that is making the statements and the inner you that doesn't feel happy and thus knows the statements are a lie. In a way it will only close the door on your intuition further and won't make you feel any happier. How could you when you're lying to yourself?

If you want to discover more about this, why not go to the crystal shop, walk around and try to have your heart open. Feel. Not read information, just look at the crystal from the heart, maybe hold one here and there. And see if there is one that actually stirs something inside of you. Raises your curiosity, or moves you in whatever way. That goes beyond merely looking at pieces of crystal from the head. That won't work.
Maybe you could compare it with walking through a group of people looking for the woman you love. That state of being -more from the heart and feeling- would be entirely different than for instance walking through the aisles of a large warehouse filled with vases, looking for a green vase. That'd be more mental. Did you need to know the science and the chances of meeting the woman of your dreams when you went out to hopefully meet her? Did you rely on science to figure out if that woman was a good match when you met her? Or was it a feeling thing? A click, connection, etc.

So look at the crystals as you'd look at the people when looking for the woman you love and see if there is a crystal that calls you. Then pick it up, feel it, look at it, and if you wish then -and not any time sooner- read the information.
And maybe you find any that time. Be okay with that too. It may have taken you time to find the woman you love as well
But doing something like that can help you get more into your heart, and start to open you up to your intuition.

I like the sound of this:
"Maybe you could compare it with walking through a group of people looking for the woman you love. That state of being -more from the heart and feeling- would be entirely different than for instance walking through the aisles of a large warehouse filled with vases, looking for a green vase. That'd be more mental. Did you need to know the science and the chances of meeting the woman of your dreams when you went out to hopefully meet her? Did you rely on science to figure out if that woman was a good match when you met her? Or was it a feeling thing? A click, connection, etc."

But if that's how we tune into the crystal's properties, it's completely subjective and makes the claims on sites like I linked to above as some salesmanship B.S.

Up to a point, yes, but not completely.
If you take rose quartz... they all have the energies that you always read. But... within the group of rose quartzes you will find that each has its own personality. I think this is why you would feel called to one particular rose quartz piece and not another.
That piece will still have the overall rose quartz energy though!
It is that way with each type of crystal.
Best thing I can advise I think is to try to not make it too mental a thing. Just experiment with it, have fun with it, don't try to explain it. Feel! Enjoy it. And don't need to feel something because then you're forcing it again.

Maybe again use the example of a group of women. Now we specify this group and make them all loving, warm-hearted, gentle women. Like rose quartzes. If you walk through that group you will not like them all, will not feel drawn to all, even though in essence they all have the same qualities. There may be one or two you like, or maybe none at all.
It's like that with rose quartzes. And any other crystal for that matter