Gemstones have been used for centuries as meditational aids and magical magical foci.   Each  individual type of  stone has different properties.  Here  are some  healing and spiritual  properties from  a list I have.

These descriptions are based on ancient legend and lore:

Agate: Moss Agates considered to be most powerful.  Aid in
          restoration of energy, used  in healing, and believed to  bring wearer
          happiness, wealth, health, and long life.  Increases
          ability  to   ward  off  self-induced  anger   and  inner  bitterness.

Carnelian-gives protection and energy.   Moss green-balances emotional
          energy.     Moss  red-balances  physical  energy.     Blue  lace-gives
          tranquility.

Amber:  Powerful  healing  stone  with large  amount  of  organic
          energy.  In ancient times, ground to  a powder and mixed with honey or
          oil  of  roses  for various  physical  problems.    Filters germs  and
          infections and  has the power to  disinfect.  Worn around  the neck to
          help fight infection and respiratory diseases.  Lifts the spirits.

Apatite: Promotes communication and mental clarity.

Amethyst:  Increases  spiritual  awareness,  has  a  calming  and
          soothing influence, has the ability to transmute negative into
          positive, and is very effective as a healing stone.  Warmed and placed
          on  the  forehead and  temples, it  is good  for  headaches.   Has the
          ability to draw through it forces directed towards the body and repels
          vibrations which the body doesn't need, thus releasing only the energy
          patterns beneficial  to the body.  Best worn in healing near the heart
          center.    Opens  up  spiritual  and psychic  centers.  Helps  prevent
          drunkeness.

Aquamarine:  Calms nervous tension.   Calming effects of the sea.
          Used to help banish fears and phobias.  Means seawater.
          Soothing and cleansing.

Adventurine:   Increases   perception   and   creative   insight.
          Stimulates opportunity and motivation.

Azurite:  Powerful  healing  stone, invokes  spiritual  guidance,
          opens psychic eye.  Good for dreams and improving psychic ability.

Bloodstone:  Stimulates   flow  of  energy   for  healing   blood
          circulation, stops hemorrhaging.  Removes emotional blockages.

Citrine: Stimulates openness and accelerates the awakening of the
          mind.  An aid to the digestive system.  Helps eliminate
          toxins.   Encourages tremendous healing  on the  emotional and  mental
          levels,  helps unblock  subconscious fears,  and  serves as  a natural
          relaxant.

Coral: Balances  physical energy  and relaxes tensions.   Carries
          the creative vibrations of the sea.

Emerald: Promotes creativity, stimulates perception  and insight,
          and strengthen memory.  Beneficial effect on the eyes.

Flourite: Opens and softens the way for the use of other stones.
          Excellent used in aquariums-provides needed minerals.

Garnet: Balances hormones, good for mental depression, enhances
          self-esteem,  alleviates   bad  dreams,  and  encourages   success  in
          business.  Thought to assist in seeing into past incarnations.

Hematite: Calming to the emotions. Worn as an amulet to confer
          strength and procur  favorable legal  judgements.  In  Egypt, used  to
          reduce  inflammation and treat hysteria.  Considered to be a grounding
          stone.  Helps maintain balance between body, mind, and spirit.

Ivory: Spiritual protection.

Jade:Stimulates practicality,wisdom,and universal attunement.
          Thought to provide a link between the spiritual and the mundane.  Most
          revered by the Chinese.

Jasper: For energy balancing of emotions and stress.

Lapis  Lazuli: Stimulates  wisdom,  truthfulness, &  psychic
          experiences, healing  and strengthening  when worn  next to  the skin.
          Strengthens mind and body to spiritual awareness.

Malachite: often used as a child's talisman to sleep soundly &
          protect  from  bad dreams.    Stimulates  clear  vision  and  insight,
          represents  hope and  inner peace,  believed to  protect from  danger.
          Increases abundance in all areas of life.

Moonstone: Brings good fortune. Reflects the wearers being and
          feelings.   Promotes unselfishness.   Opens the heart  to humanitarian
          love and hope.  Good for protection while travelling on  water.  Gives
          clarity to  spiritual understanding.  Good  for pre-menstrual symptoms
          and balancing to the reproductive system.  Used to ease childbirth.

Pearl: Stimulates feminine qualities,used to focus attention,
          helps  pull  together  mental  and spiritual  forces,  peace  of mind.
          Represents purity, modesty, & gentleness.

Peridot:  Dispels fears,  guilt,  and depression.   Used  to
          counteract negative emotions and  healing of the spirit.   Affects top
          three chakras.   Once worn as a means of  gaining foresight and divine
          inspiration.

Quartz: Amplifies the healing energy of the one using it.  Used
          to help draw out pain.  Able to tap into the energies of the
          universe.   A good stone for meditating  on.  Works primarily with the
          Third Eye center, also relates well with the heart center.  To be able
          to  tune into the quartz  promotes clarity while  concentrating on it.
          Also affects the crown chakra.  Very potent and often  worn to protect
          from  negative  vibrations.    Cleanse  regularly.    Rudilated-rutile
          needles  help  focus attention.    Smoky-good  for  calming the  mind.

Rose Quartz:  Vibrations of universal love & inner serenity.

Ruby: Increases  vigor, renews  vitality and cleanses  the blood.
          The stone of courage.

Topaz: Calms  emotions, protects  against external stresors.   To
          restore physical energy & quiet emotional nature.

Tiger Eye: Very powerful protection, clarity of thought.

Tourmaline:  Causes the  wearer  to be  more flexible,  more
          understanding  and more  objective in  purpose and  reason.   Calming.
          Each person has a different response to this stone.  Causes a
          reaction  in   the  intestinal  tract.     Black  and  Crystal-removes
          negativity and cleanses.  Some  say it should not be worn  as jewelry.
          Electric and magnetic properties.

Turquoise: Vibrates calming radiations, protective,and restores
          healthy  mental  attitude.    Stone  of  friendsship.    Balancing and
          healing.   Great strength and  vitality.  Takes  on characteristics of
          the wearer.

This list is by no means complete -- nor does it give you all ht einformation you may want.

Crystals
By Matrika

The Care and Feeding of Crystals
by Matrika

Inner Light's List of Stone & Their Properties

Energy and Crystal Work Book
Compiled By Greg Booras

Ayurvedic Gemstone Properties (including a birthstone chart)
by Unknown

A Guide to Crystals and Gemstones
By Nita Morgan, Widdershins Jewellery

Cleaning Your Stones
by Laurie

The Healing Power of Stones, Gems & Crystals
By Trisha Ellis

Therapeutic Gemstone Properties
by Unknown

More Crystal Information
by Unknown

Gem & Stone Personality Test
for fun!

Powers and Magickal Uses of Stones
~Ma'at's Book of Shadows

Crystal Healing
by Tyrrany Sea <tyrranysea@hotmail.com>

Star Stones
from the Rocky Mountain Pagan Journal, 1986