Effective use of crystals

I often wear certain crystals. But does it actually makes any sense? There is written in VT "Despite the usage of minerals being common practice among contemporary occultists and seeing a strong resurgence within popular culture, their usability is far from simple and modern approaches often lack depth and mastery, promoting rudimentary a shallow take on the exploration of mineral magick, resulting in poor esoteric results". So are commonly used techniques, actually worth trying? Or are they too weak to consider? Is there possibility of initiation/attunement of mineral by ourselves to some degree?

And is unconscious cycling (in people with intense cycling) enough to clear a crystal when worn often?

How do crystals connect with person? If I understand correctly, they also form a link, right? But does the placement matter? Or not wearing for some time is affecting the link? And what happens when wearing more than one crystal, and how that affects placement?

Can person without access to any higher level knowledge make effective use of crystals?

Can you recommend some source from which one can learn how to use them effectively?

(the excerpt comes from chapter "Magick" VT p 180 , not the "Minerals")

if there is no effort placed on the individual level in order to learn how to sense, wield and heighten psychic energy, those questions will never be answered. No matter what anyone tells you, the best way to find out what works and what doesn't, is to try it out yourself. This applies to all sorts of occult knowledge, where the message can often be hidden where words are not to be found. I have seen you asking questions many times here, and that is a good thing but keep in mind that a lot of these questions are not to be found online whatsoever, and you have to begin practicing yourself and form a connection to the spirit world in order to know where to find answers about things like that, in whatever form that may be. It is very rare to find definite answers about some of those things, but even so it is still definitely worth pursuing the path of magick and self mastery for many other more important reasons. Having said that, in my personal opinion, the energy links formed with crystals work similarly to how the ones between humans do. The longer someone uses them the stronger that connection becomes, and yes, everyone can use them to varying degrees. I think that part of the book was in order to show there is actually a big difference to the contemporary use of crystals by New Age dabblers as some sort of fashion accessory or cure-all magic pill, in comparison to the highly advanced and cryptic wisdom that the Aset Ka is known to have been in possession of for many many years, regarding their effective use in advanced energy work and wand making as potential weapons and tools of power that could be misused in the hands of the wrong people.

I also wanted to clarify, I don't see anything wrong with using them as fashion accessory and other stuff like that, but people need to remain aware that they are far more potent in reality and those other things shouldn't distract people from their other many, and deeper functions

This is kind of pointless as you need actual subtle sensitivity for your questions to even matter. Sensitivity needs to be developed and there are some things you can't learn just from a book. 
So you'll need to sit down with a crystal and learn to sense its energy, work with it, and experiment.

I do have certain sensitivity, and I'm working on having more of it, even started with some energy healing. However, I don't think it's enough to have intuition, AB clearly says about specific practices, for example the use of fire. Fire is probably used to initiate a wand for actual warfare (probably that's what is meant by 'active magick').

What interests me most is the 'special mineral magically connected with their energy fingerprint'. Is that about some ritual? Or is this attainable to certain degree? What I'm really asking is what should be done with crystals beyond cleansing ('promoting a rudimentary and shallow take on exploration of mineral magick, resulting in poor and weak esoteric results', ''While techniques of energy cleansing can be easily learned, to make proper use of a mineral in direct energy manipulation, and by taking advantage of its highest potential or magical efficiency, the geological tool requires submission to a procedure of initiation crafted for the specific mineral to be attuned').

So it's especially about the 'atunement' part of 'Talismans must cleansed, attuned and empowered according to ancient knowledge.

I can draw something of a comparison to when you attune to magickal artefacts in a few tabletop systems I use. You need to connect to the item - decipher its particular vibration, connect to it and interweave it with yourself both when it is in use and inactively. It might be something of a simplistic and pop culture parallel but it is what immediately came to mind.

Going off what you have written and drawing something of a parallel with how I am beginning to connect to plant spirits, it sounds a lot like establishing a relationship. There is that first step, that initial approach and that initiation of a connection.

It doesn't state that a specific procedure is required (going off the word choice of 'a procedure of initiation' rather than 'the procedure of initiation') which suggests to me that how you go about aligning with the tool and it with you may be unique according to your respective technique and intended purpose for it.

As Rhea says, sensitivity to a particular crystal's vibrations and signature takes time. Learn how it vibrates. Does it feel better in some settings or contexts than others? Does charging it in different circumstances feel better or worse? Like how I establish a relationship with the energy of the sacred spaces I use, it isn't a one-visit realisation - it takes repeated visits, openness and a certain sense of stillness.

I also can relate attunement to tarot -- as much as some of what I have encountered so far is rather fluffy, the principle of some decks just not aligning energetically with the individual makes quite a degree of sense, depending on the particular deck and if it has been produced and intentioned with serious purposes in mind.

I hope I can contribute to this subject writing a little about my experience.
Many years ago while studying occultism I started with crystals.
While shopping I found a copper tube with a crystal in the extremity,it looked like a wand or baton with a crystal in the end. I test it few times trying to send telepathic messages, It only once worked undoubtedly... at that time I thought it was a amplifier of thoughts or something like that. I did not continue my research but I have many crystals around my home. By the way the person that sold me around 50 crystals last time told me to by SELENITE bars because it recharge the quartz crystals.

Recently I found called "Cylinders of the Pharaoh" or "Wands of Horus" by Valery Uvarov, it is made of metal and crystals, take a look it is impressive. Wands of Horus

I still want to by it, but the original by Uvarov, not the lower quality ones.
I had many conversations with people that constructed a crystal crown, and others that learned how to vibrate in the same "frequency of a crystal" so they don't need to use crystals anymore. It is a fascinating subject. Which I am still learning.