Quartz crystals are like little tools, or perhaps like discs containing information from the Earth Mother. 
Including a quartz crystal cluster in a room can energize the room, disperse negativity, stimulate concentration, combat electromagnetic stress and increase intuition. Wearing or carrying a quartz crystal of a given sort can help you feel more balanced and lightly-grounded, is calming and strenghtening to the auric field, can help conduct energy in the body, boost the immune system, open and cleanse chakras, and is capable of amplifying "subtle forces" including thought energy. When a crystal is cleared and then charged correctly, it can generate a protective field for the user.
There is a world of learning in just the various aspects of quartz crystals... they come in a dizzying array of formations, textures, and with all sorts of inclusions. What I have discovered is that you cannot always go by the books about the metaphysical properties... they are at best a general guide, but by no means the last word. For 
example, "Tabular Crystals", which are more flat in formation, are often considered to be "healing crystals", but from my personal experience in collecting these crystals, I can tell you that they can have just about every capability... I have some tabbies that are generators, some are for channeling, and some that are also Lemurian crystals. The point here is that you have to tune in on the crystal to find out what it is for.
One of the most comforting crystals I have come across is the "Elestial Quartz" crystal, also called "window quartz". These were formed under water when the Earth was young, and many contain drops of promordial water. The multi-layered form of this crystal, with layers beneath layers, is generally considered ideal for accessing, understanding and healing past life issues... 
the ol' "onion layers" approach. I have found that these can also assist one in going with the flow, smoothing the flow of things for you, and even assist in self-actualization. these are great to hold in meditation. Many can feel the water energy within them.
Lemurian Seed Quartz is a specialized form. Most people who are attracted to these find that such crystals help them to feel more at home in their skin or in the world, it gives them the empowering feeling of past lives in Atlantis and Lemuria. Many of these are also "Laser" quartz, meaning that they are excellent for conducting energy.
A lot of research into various forms of quartz over the years. A former IBM researcher, Marcel Vogel, discovered that he could remove some of the inherent unpredictable aspects of natural crystals by hand-shaping them along a pstraight vertical axis through a perfectly shaped point to conduct healing energy. Vogel-cut quartz is one of the most energetic forms available.
Aura Quartz" is not naturally-occurring. The multi-colored sheen is produced when a natural quartz piece is electroplated to infuse it with different metals (indium, titanium, gold, silver, zircon, etc.) in a laboratory. The result is a profound energetic enhancement of the crystal and its original programming. I have personally experienced aqua-aura quartz that loved to be worn but not with any other stones... it wanted me all to itself!
When I create a piece of quartz jewelry for a person, I have to first tune in to that person's Higher Self, then check each piece in my collection to see which one will work best for that person at this time. Having selected the piece, I have to determine the orientation of the crystal and which other stones are needed with it. Some people need double-terminated (two-pointed) quartz to help them move energy through their bodies, some really need the single-terminated to help either move energy up or down, so I must wrap the point facing the apprpriate direction for them. The real work comes when the physical piece is finished and is ready for the energy work to be done to completely cleanse it of all static or negativity, then energize and program the piece on a Higher Self level for the wearer. The end product is an energetically positive and aesthetically pleasing tool to assist that person on their path.
