Clear and Snowy Quartz
Quartz crystal is the second most abundant mineral in the planet, next to feldspar.  Made from the two most common elements in the Earth's crust, silica and oxygen, the tetrahedral molecule SiO4 shares the O2 element between them creating the crystal matrix and chemical name of SiO2, silica dioxide that is commonly referrred to as quartz.  The hardness of quartz, 7 mols, and it's relative imperviance to chemical weathering both contribute to the longevity of this mineral and therefore it's abundance both on and below the surface of the Earth's crust.  Quartz is piezoelectric, that is it generates electricity when it has a mechanical stress placed upon it, a characteristic that has proven invaluable in the creation of crystal oscillators.  Crystal oscillators produce very consistent, very precise frequencies that can then be used to keep very accurate time.  Both in time pieces and electronics the ability of quartz to create the opportunity of precision time keeping has proven invaluable.  Silicon Valley carries the name of the element that has fuelled the information age because of it's ability to transmit electricity and store information and where would our world be without computers and the design capabilities they have allowed for as we continue to advance our technological knowledge and apply such knowledge to the human condition?

It is perhaps no coincidence that our home planet Earth, ourselves, human beings, and quartz crystals all emit infrared energy at 10 microns, (micrometers).  Infrared was discovered in 1800 by astronomer William Herschel and is an energy source that is less than red light and was found to be the cause of the change in thermometers. Many of the healing properties attributed to quartz, it is believed, is the result of the direct relationship betwen the emission of infrared shared by humans and quartz.
Snowy Quartz is created by inclusions of gas and fluids, particularly water, within the crystal creation process.  Often the crystals are growing in a closed enviornment and once the available gas and/or fluids have been encased within, new clear secondary crystal grows unempeded around the primary crystal. The resulting crystal is known as a phantom crystal  because of the ethereal, ghostly presence created by the inclusions such as displayed in the picture above.  
For millenium crystal has been recognized by humanity for it's beneficial, metaphysical properties.  Used by the ancients and First Nations people throughout the world, quartz crystal has played an integral role in ceremony, healing and meditative practices, traditions that continue to this day.  Proving that technology is not necessary for humanity to recognize and interact with the natural world, what has been discovered, technologically, about quartz has been known by mankind since it was first discovered.  Quartz moves electricity and energy.  It also stores information meaning that it can be programmed with out thoughts directly, just as it is in our computers.  All of the benefits attributed to quartz are a reflection of this ability to facilitate flow.  It balances, transmits, amplifys and absorbs.  Quartz is the universal crystal because it is the basis of so many types of crystal, all of which reflect the powers of the mother stone to a greater or lesser degree.  Snowy quartz is the female yin to the male yang that is the clear rock quartz and the phantom quartz brings an even more enhanced balance to the circumstances it is used in.
Smokey Quartz
True Smokey Quartz is seen by some as being the most important, the foundation stone, upon which work with all quartz rests.  From light grey/brown to the almost black, Morion variety, real Smokey quartz gets it's distinctive hue,from the free silicon created from the silicon dioxide, as a result of being irradiated by the radioactive rock surrounding it.  This process can take millions of years to produce this effect, an effect that can also be contributed to by impurities within the quartz such as aluminum.   Quartz can be exposed to radiation, x-rays for example, and turned into Smokey quartz but this synthetic version is not as highly prized as that which is naturally occurring.    Metaphysically, the true value of Smokey quartz is it's ability to absorb negative energy's and the patterns they create.  The benefits of the this energitic cleaning they provide cannot be overstated, for once the negative has been transmuted, the space is now available for positive life affirming energies to contribute as only they can, in an unempeded, free enviornment.  
      Associated with the human base chakra, the Smokey is the foundation crystal supporting everything that is physical within the human experience.  The foundation must be secure before one can hope to move ahead productively, and Smokey Quartz brings balance and energy flow to the base chakras facilitating the health we all desire.  They also help to disrupt the negative effects of thought that is depressed, angry, anxious and/or resentful and can be especially helpful in this regard when it comes to our sleep and the dreams we have and remember.  Negative thinking will interrupt our ability to connect with the potential that is the reality we access in our dreams.  Disconnection from our energy source, which is why we sleep in the first place, to recharge only serves to deepen our negative thought patterns.  This cycle can be interrupted and reversed by the gentle aid of Smokey quartz so sleep with your Smokey and let it come into your life. 
Amethyst, the protection stone,  actually derived it's name from the belief, probably more of a wish, that the stone protected it's owner from the effects of alcohol.  What the stone brings to it's owner is the gift of sober mind.  Varying in colour from lilac to deep purple, also known as the Bishop Stone, the Amethyst symbolizes piety, humility, sincerity and spiritual wisdom. Relating to the crown chakra, the Amethyst connects us to our higher selves more so than perhaps any other crystal and can be used both in meditation and while you sleep to facilitate dreaming.  Once considered one of the five most precious stones, there is still some debate as to how the crystalline structures actually form. The geodes that Amethysts are found contained within most certainly form in gas pockets created in lava, pockets that become filled with silica rich water.  Trace elements, especially iron impurities result in complex crystal lattice substitutions that along with irradiation by surrounding radioactive rock are responsible for the regal coloration.
Citrine derives it's name from yellow to orange color, and natural citrine is actually quite rare, compared to that commercially available which is primarily heated Amethyst.  It's colour is primarily due to traces of the element iron within the quartz crystalline structure.  Natural Citrine is often confused with topaz, though the difference is quite readily apparent when the hardness of the two is tested.  Topaz has a Mohs hardness of 8 while citrine, a quartz crystal, is 7.  The vibration of the natural Citrine is cleaner, smoother than it's fabricated counterpart though it's colour is generally not nearly as striking or dynamic.  Referred to since antiquity as the Merchant Stone, Citrine reputedly heralded financial stability and success to those who used it, though it's real strength lies in it's connection to the solar plexus chakra.  Powered by the sun, Citrine warms, cleanses and energizes and can be used to cleanse all the chakras.  Regardless of it's origin, Citrine has a joyful vibration that can help one to deal with the effects of depression, release anger and learn productive communication skills.  As an expression of quartz, Citrine can establish a flow of energy where physical and emotional blockages have created stagnation allowing  optimism and creativity to readily move into the psyche and life of those that use it. 
Amegreen quartz crystals have a soft balancing vibration that blends the energy and vibration of Purple Amethyst, Prasiolite and White Quartz.  Together they create a trio that is greater than the sum of the three parts, emanating a surprising energy that connects humanity with the Divine realm through the true centre of the human being, the heart.  The energy of all three of these powerful stones combine synergistically in this one stone.    The energy of the Purple Amethyst that is embodied within these stones, creates a connection to the higher chakras.  This resonates from the third eye right up to the higher transpersonal chakras. The white quartz emanates the pure white light of the Divine realm. The Prasiolite energy brings high vibration energy down from the higher realms to the heart, grounding this into the physical, then continues to take the energy down to the solar plexus chakra, all the while facilitating the flow of energy from the physical up to the higher chakras.  Truly a gift from Creation, Amegreen has a place in any crystal workers collection, and compliments any space.
The word Prasiolite is derived from the Greek word meaning, leek, attesting to the green colour of this type of quartz. It is generally agreed that the color of this quartz is the result of heating of amethys, usually by volcanic activity or so it is suspected.  Regardless, the stone can be translucent to transparent and works with the heart chakra, helping to energetically link the physical aspects of the Human self with the spiritual aspects of Higher Self. Prasiolite brings the higher vibration energy of Divine though the heart and into the physical.

Prasiolite helps to ease discomfort for those who find it difficult to express emotion. It is a reminder that all are part and parcel of the Divine, unconditional loving Source. Those who have issues of self-worth or lack self-confidence will find working with Prasiolite helps to foster a deep appreciation and acceptance of self.

Prasiolite is an excellent stone to use when connecting the higher energy of Source to the grounding energy of Earth. This allows a powerful healing energy to flow from the heart into the Earth, removing any discordant, negative energy and filling the space with the capacity for renewed growth. Healers who work with stones also find that Prasiolite will work in a similar manner. Higher, healing energies flow from Source, into the heart, and through the hands, allowing the removal of these energies.
Thank you to for this contribution.
Super Seven
If you could own only one stone, perhaps the Super Seven, also called the Melody Stone should be the first choice because of it's range of contributing vibrational energies and the ease with which this stone can be used.  The combination of Clear Quartz, Amethyst, Smokey Quartz, Cacoxenite, Rutile, Geothite and Lepidocrocite facilitates balancing of the energies of all of the chakras and just as it balances those it comes into contact with, it balances itself.  This particular crystal has the amazing quality of never needing to be cleansed or cleared because of its perfect balance of vibrations and the sceptor to the right is also a beautiful balance of yin and yang energies.  From the base chakra, through to the crown chakra Super 7’s are relentless, they never give up! They are here to awaken the personality to its divine magnificence, and will push and push until the owner surrenders to transformation and growth. They are here to awaken humanity to an enlightened way of being, an awareness of the physical supporting the spiritual, of recognizing the necessity of walking this Earthly path.  When a Super Seven stone comes into your life the message is clear....."It Is Time!"