It may seem strange to have all of those words in the same sentence, but stay with me here, I really do have a point to make, that I think you might find useful.
I am going to make a crystal comparison to the use of food in our daily lives as an aid to health and healing, putting aside the obvious fact that we do have to eat to stay alive. We do not have to use crystals. We get that.
Clients will occasionally ask me to create a piece with divergent energies. For instance, to create for them, one comprehensive necklace, intended to fight their cancer, increase libido as well as psychic awareness, win the lottery, help with body odor, and attract a new lover. I'm not saying that it isn't possible, but from where I stand, it isn't a terrific idea to combine all of those energies in one piece, intended for daily wear, and the average person who does not know much about color, chakras, or crystal qualities and potential combinations, might think I am being a prima donna, or just want them to buy separate items. This is really not the case, I would love to wave my proverbial magic wand, and hand over the cure-all, but honestly, it doesn't work like that. I can think of only a very few mineral candidates that would even come close to covering all of those bases, and they are not mainstream items.
The analogy I am making is that even though tuna fish is tasty and good for you in several ways, and watermelon is equally delicious and also good for you in other ways, you probably wouldn't want to put them both in the blender together. It might even make you feel worse rather than better.
Unfortunately, to make it even more complicated, there are not any provable hard and fast rules that apply to using crystals and minerals, but common sense and cross referencing the material that others have explored is usually a good idea. Using a business such as mine, or the many many other wonderful practitioners and authors that have done the research for you is always a good idea, or join one of the crystal interest groups online that have open discussions and tons of free advice. Try to gather some information about how colors and vibrations effect our well being.
I even hate to generalize, but I will go so far as to say, as with food, things that are similar, or complimentary are a safe bet. Leafy greens will make a common salad, tomatoes and cucumbers will compliment it. Many things, including the tuna fish, can be good with it, but putting ice cream and chocolate chips on top of the salad, will not feel quite right, or even taste good. Go with your feelings, go with your intentions. Ask. Experiment. Learn.
The more time you spend getting to know the mineral kingdom, and your own personal crystals and pieces, the better you will get at discerning their properties. There are no special gifts or skills required.
I love rose quartz, and I love rainbow obsidian, however, I would not put them together and try to get opposite effects at the same time. They represent love, and protection, respectively, both good objectives, but one is low, aggressive, protective, and grounding, and the other is heart centered, light, high, and welcoming. That is just one very general example, but you get the idea..
Quartz is amplifying, clarifying, and usually energizing.(many common crystals are in the quartz family). They can usually be safely combined in many ways, with many other items that are not quartz based.
Although the overall effect is always for our best and highest good, sometimes situations seem to get worse before they get better, as you move from one stage of development to the next, or let go of a belief, pattern, or relationship that has become toxic or is holding you back, as you move towards something better. If something that has been recommended consistently makes you feel sad or angry, try something else. Everyone is unique, and has different needs.
Many crystals represent multiple things, depending on the intention and how they are combined. One person might want to carry malachite for ocular health, one for luck, another for protection, and another to amplify and manifest wealth. All would be correct, and could be accentuated by adding more items along the desired lines of the energy you are trying to activate.
As you become more experienced, and more curious, you will find your own personal ways of doing things, and the crystal friends that are right for you.
In the meantime, if you want to eat mint chocolate chip ice cream with spinach and a veggie burger, go right ahead.
Peace. Naked Fairy Apothecary