Kunzite
Kunzite and Kunzite General Gem Information:
Kunzite is a variety of Spodumene (lithium aluminum silicate) that happens to be either a pink hue (ranging from very light/almost transparent to deep and purple). Kunzite is a very freshly discovered gemstone, discovered in California in 1902. It is known for its color and its brilliance, faceted Kunzite appears to vary in brilliance and color depending on how you view it and how the light hits it. One irritating thing about Kunzite is that the color can fade in sunlight over time, changing the stone permanently.

Other Properties:
Kunzite is said to have many different mystical properties, including increasing devotion and understanding as well as bestowing inner peace. It also helps to relieve stress and anxiety, as well as helping the wearer to interact better with others. It is said to help heal fractured souls, and help heal damage from past lives.

Notations on Wearing Kunzite:
The signs associated with Kunzite are Leo, Scorpio and Taurus.

Links between Kunzite and Kunzite of the Shittenou:
Kunzite is the strongest of the Shittenou both physically and mentally, and this gem is given quite a lot of mystical properties (though most are mental/emotional). Of particular interest is the fact that Kunzite fades in light. In the manga when the brilliant flash of light from the ginzuishou is revealed, Kunzite suddenly remembers his whole past and begins to question his loyalty to Beryl and Metallia. In this way, with the light his loyalty 'faded'. Another interesting thing about Kunzite is that it is related strongly to healing the damage from past lives. Kunzite is the most interested and active in healing the rift between the Shittenou and Mamoru (as the leader of the Shittenou, he would have this role). In PGSM, Kunzite is the most determined to keep the present from repeating as the past, no matter the cost (even going so far as threatening Endymion/Mamoru repeatedly).

References:
Find Your Fate - Kunzite
Gem-by-Gem - Kunzite
Kunzite