Garnet
Garnet & Sailor Pluto General Gem Information:
Garnets take their name from the latin word granatus (grain-like/seed-like) because the crystals resemble seeds embedded inside the matrix stone. Garnet is an entire family of gemstones, with a basic chemical formula where the make up can be interchanged.
Though typically a blood red color, garnets can be found in a variety of shades; in fact garnets are the most versitale gemstones as far as coloring goes because they occur in every color except blue.
Garnets are found all over the world; including Africa, Canada, Brazil, India, Madagascar, and the USA.

Other Properties:
Associated with the root chakra, garnets are said to lend vitality and strength to the user. It also increases sensuality and invokes and releases creative ability and inner fire. The garnet is a symbol of true never-ending love and devoiton, and friendship.
Legend has it that Noah used a garnet as a lamp on the ark.

Notations on Wearing Garnet:
Garnet is the birthstone for the month of January. It is also the anniversary gemstone for the 2nd year.
Astrologically, it is said to benefit the signs Aries and Leo.

Links between Garnet and Sailor Pluto:
Garnets are strongly connected to Sailor Pluto. Her talisman is the garnet orb, her eyes are the deep red color that garnets typically are. Pluto uses her garnet orb with the other talismans, calling forth the Holy Chalice and lending its strength to Sailormoon.
It is the devotion of the garnet that fascinates me in correlation with Pluto, however. Despite the lonely task ahead of her, Pluto devotedly stands and guards the gates of time.

References:
Find Your Fate - garnet
Gemstones - Garnet