The color of stones is really just as important as what kind of stone it is. And when you pick a stone, as with any magick, it is important to know how this perticular stone, not the kind, but the individual stone, reacts to your own body chemistry, your feeling about the stone is always more important then the kind, or color. And make sure before buying your stones that you know that what you are thinking your buying, really is what it says it is. Alot of stores sell these magickal semi-precious stones.
Or you could just find stones in nature, preferably in a magickal spot you feel power.
Then, once you buy or find your stones, you must cleanse them. Sometimes they don't need cleansing when you find them in nature, but it's better to be absolutely sure that you don't get any negative energies mixed in with you magick. Or even if the other energies aren't negative, it's best to be sure that when you charge a stone, that's all it's charged with, it works best that way, and you can be sure that your magick is done purely.
I'v read many different methods for cleansing, so whatever has worked for you before, or what you trust will work, or whatever you'v read is best for whatever certain thing your planning to use your stone for, you should do.

Misc. stones:

Kunzite:
Is a very expensive stone. It helps a person to become more relaxed but also more disciplined. It appears to be Earth-grounded in vibration.

Pyrite:
Also known as fool's gold. Money, prospeity, total success. Ruled by the sun, especially attractive to the dragons of light, mountains, and the earth. One can use a flat surface of pyrite as a scrying mirror combined with other stones, it intesifies good luck.

Moonstone:
Gaining occult power, rising above problems. Ruled by the moon; attractive to all dragons. It's good for enhancing the moons powers over gardening. It strenthens divination abilities. The moonstone is a reflector stone in that it reflects whatever emotions or vibrations are being given of by the user.

Rock Crystal:
An amplifier of magickal power; psychic work. All dragons are drawn to this crystal, but earth dragons especially.

Crystal Quartz:
has been used in magick and spirital endeavors in a great many cultures around the world. Clear crystal was known as the star stone in early British cultures. It has been used for Scrying, both in ts pointed shape and when fashioned into shperes. Pieces hung on a silver chain make excellent pendulums. Chunks, spheres, or points of crystal act as amplifiers of magick when set about the circle. Crystal quartz can also be "Programmed" or used as power-sinks of energy, so be very aware of what you are doing when working with this stone.

Lodestone or Magnet:
Drawing power; abitlity to attract what you want. Rep. of stars and meteorites. Lodestone can be subsituted with a magnet if you cannot find the genuine thing. Lodestone sends out vibrations of attraction according to the type of magickal working you're doing.

Eye Stones:
Reprasentative of all dragons, any form of eye stone is very valueble when working with these creatures.

Cat's eye:
Also known as chrysoberyl, and it also refers to many other stones, usually olive-green quartz. It protects, increases wealth, gives protection an insight into porbs, or specualtions, and helps with healing on the emotional and mental planes.

Tiger's Eye:
It promotes energy, luck, and courage while helping with protection and gaining money.For magicians who are well balanced and willing to see themselves for who they really are, this is a great stone for focusing the power and vision of the mind and the inner eye.

Holed stones:
Stones with a naturally formed stone in them are valueble as a symbol of the hole through time and space through which dragons moce back and forth from their realm to ours, perfect for working with them. Their particuler value for a magician working with dragons is their protection while traveling wiht dragons and a center focus for returning.

Staurolite:
These natural stones look like an X or an equal-armed cross and are alos called faery crosses. These four arms represent a balance of the four elements known in magick. Protection, balance on all levels, money, good luck.

Fossil Stones:
There are a great many kinds of these; any stone having the fossilized remains of a plant or animal would fall within this catagory. Strangely enough, on of the old names used during the middle ages was "draconites." The british know them as snake stones. Protection, balancing with Earth energies, past lives, guides though other worlds. Fossil stones, with their unique connection to the past, are valuable for working with past lives. There is a slightly different vibration of power in each one that makes them valuable when traversing other worlds or times.

Coral:
Coral is not really a stone, but the skeletal remains of a sea creature. However, it has a long history in magickal workings. It is best if it has not been worked (that is cut, polished, etc.) and comes to you wiout being harvested. Coral is helpful becuase of its protective qualities. It guards against unwanted astral entities, negative magick, accidents, and acts of violence.

Geode:
A geode is a round, rough-looking rock which usually reveals a hollow center lined with crystals when split open. Sometimes inricate mineral petterns are exposed instead. Either way, geodes are very beautiful and fascinating. Geodes which reveal a crystal-lined cave are excellent stones for magicians working dragon magick, as they resemble the dragon cave of initiation.

Lava:
The formations of lava rock is accomplished by the four elements working together. Although lava is of particular importance when working with dragons of Fire and volcanos, it is also of interest to all types of dragons, as they all breathe destroying-creating fire.

Petrified Wood:
Ancient trees which slowly had their fiber dissolved by water and replaced by minerals turned into petrified wood. It is actually silized wood. It's good for Defence, setting up barriers, exploring past lives.

Meteorite:
Small meteors that fall from space. They are good for protection, travelling from one plane of existance to another. Meterites give off vibrations of protection, while also helping the magician to understand any destruction-creation experiences which she/he may be experiencing.