Mankind has a deep connection with Quartz, the most common crystal on Earth. The Quartz family grows in a staggering amounts of different ways, all based on the same atomic shape. Quartz atoms grow in perfect 'double-helix-ical' patterns, like our DNA. 
Every atom is a perfect rainbow of Divine Light - splitting the light into all seven colours. The prismatic nature of Clear Quartz allows it to split natural clear light into the full spectrum of colours, so it can be worked with / attuned with all chakras and colour centres. 

Quartz crystals are able to assist us to perform many different types of healing and Light work. Clear Quartz crystals can help all cells to attain their true optimum state of being. 

Rock Quartz will perform most of the Quartz functions, but a perfect and complete pointed Quartz crystal is most ideal for working with. They are able to channel healing energy direct through their bodies, from base to tip, and out through the point. These crystals can teach us how to channel more purified Unconditional love and healing energy into our environments and to our fellow beings. They cleanse, clarify, lighten and amplify the healing energy, and then focus it via the point. (A crystal with a slightly chipped point will not be able to focus energy so clearly.)

The Clear Quartz energy is naturally very stimulating and focusing. It is not generally a soothing or calming experience to work with Clear Quartz. It can help to attain clarity and calmness in any situation, but is itself a Storm element crystal, and works with the transformational and energetic aspects of the Storm energy. It is both an activating and balancing crystal, whereas most crystals are one or the other.

Natural grown clear Quartz crystals are energizing, activating, and bring light into their surroundings. As they can split light into all the colours, they will seek to enhance cells of all different types and vibratory rates. 
These crystals can aid each cell to rid any unwanted/negative memories/patterns which may be stored, and encourage new regenerative growth, and optimum vibratory frequency. When a cell is not vibrating at its optimum rate, dis-ease/malfunction is likely. New cells are made all the time, but are copied as exact replicas including any disharmonic blueprints. Aside from many other benefits this enables us to sense more clearly the reality of any given situation, and what dynamics are at work. This helps us to stay true to ourselves, and maintain living in a place of LOVE. 
 
Key crystals are good to help you unlock answers to questions you may have. You can access them in different ways. You may gaze into them during meditation, or simply close your eyes and enter the energy of the crystal, imagining it opening and see what answer you get to a question you may ask. I like to put my thumb or finger into the Key as I meditate on the question. There are many different ways, use your intuition for the best way!
 
Rainbows are crystals of hidden joy, optimism, and understanding.  They help us see the beauty in mundane things. 
They are useful in spiritual healing, meditation, and as talismans. 
They are primarily used when the need is to deal with grief, loss, or pain.  
They help us overcome sorrow.  They show us the hidden powers of the Universal Life Force, and they help us stimulate all the parts of the brain in solving problems.  
As meditation crystals they are used in similar efforts, finding answers to loneliness, loss, heartbreak, and disappointment. 
As talismans, they offer us a daily reminder that the Life Force is ever present and that we can find beauty if we look carefully.