I told my wife about this thread and she referred me to a number of good sources on the magical significance of various gems and other stones, herbs, and incenses. I encouraged her to get an account, but she didn't seem interested. Here's what she had in a catalogue from Mystic Trader, a company from Riverside, CA that sells at the Ren fairs up and down the state:
Stones
Agate, Blue Lace: Stops stubbornness
Agate, Botswana: Helps to brig peace & calmness
Agate, Brown: Heals the sick, brings riches, happiness, health & long life
Agate, Lace: Helps build self-confidence
Agate, Moss: Cures eye disease, abundant harvest
Amazonite: Raises self-confidence
Amber: Lifts the spirit
Amethyst: Cure for drunkenness
Adventurine, Orange: Brings good luck & abundance
Bloodstone: Guards you against deception
Calcite, Green: Clears toxin from the body
Carnelian: Gives you courage, helps you to speak boldly & well, brings you friendship
Chrysoprase: Helps you ease any bad situations, brings gaiety & joy
Citrine: Protects against jaundiced liver ailments
Copper Helps cure arthritis and rheumatism
Eilate: Brings one feelings of love
Fluorite: Rekindles sexual appetite
Garnet: Protection from evil energy, brings you loyalty & devotion
Hematite: Stops bleeding, clears bloodshot eyes
Iolite, Blue: Helps you be a leader
Jade: Essence of Love, brings you strength & power
Jasper, Indian: Removes energy blocks in the body
Jasper, Leopard skin: Helps channel positive energy
Jasper: Cure for snake bites, drives away evil spirits, brings rain
Jet: Helps come up with constructive solutions
Lapis Lazuli: Cure for melancholy & fever
Lepidolite: Brings you peace, harmony & oneness
Loadstone: Brings you sympathy and love
Malachite: Keeps evil spirits away
Moonstone: Brings you good fortune, arouses the tender passions
Mother of Pearl: Reduces fear....Calming
Obsidian, Snowflake: Slows one's pace
Obsidian: Reveals the truth
Onyx: Provokes discord & separates lovers
Opal: For prayers & assurance of fidelity
Paua Shell: Reduces stress
Pearl: Chastitiy & purity
Peridot: Frees the mind from envious thoughts & treats disease of the liver
Petrified Wood: Helps calm anxiety
Pyrite: Protects against crocodiles
Quartz, Green: Brings fertility, abundance, & good luck
Quartz, Rose: Brings love, deals with matters of the heart
Quarts, Smoky: Removes negative energy
Quartz, Strawberry: Helps one to remember dreams
Quartz: Saves you from bad omens
Rhodochrosite: Increases long term memory
Rhodonite: Gives you confidence
Selenite: Assists the growth of trees & plants, brings good luck
Sodalite: Promotes courage, dispels fears & guilt
Sulphur: Use against colds & pains in the body caused by witches
Tiger Eye, Gold: Higher influences will come to you
Tiger Eye, Red: For health energy & courage
Tiger Eye, Blue: Keeps one active
Topaz, Blue: Brings much truth & wisdom to you
Topaz: Stimulates one to use the mind
Turquoise: Pulls one into the experience of unconditional love
Unikite: Enables one to take charge of one's life
Zoisite & Ruby: Makes one feel giving and happy
Color chart
Black: Protection from the evil eye
Blue: Truth, wisdom & good health
Gold: Brings higher influences
Green: Abundance, fertility, & good luck
Purple: Psychic abilities & powers
Silver: Removes bad omens
White: Purity
Yellow: Power of the mind
Just typing this, some ideas come to me about how I might use this in-game: Brown Agate is clearly something every adventurer should carry an abundance of. Obsidian might make a good material component for a
zone of truth spell. How about a goblet or tankard hewn from Amethyst? Enchant it with
neutralize poison and you've got a vessel that the character can drink from all night with intoxication. Gold tiger's eye might be a suitable focus or material component for
commune, contact other plane, or even
planar ally spells.
Protection from evil or
magic circle against evil might work better if malachite were a part of the casting. Finally, smoky quartz is just too cool. Remove negative energy could be very helpful, depending on the campaign. what about a +1 to turning attempts or turning damage?