Navajo TurquoiseThe ones with the black lines in them are called Navajo turquoise and helps you to stay in a place of love and connectedness with others. By doing this it can make you feel at "home" no matter where you are. It is a combination of turquoise and sard (sard being the lines). turquoise by itself keeps one in the feeling of unconditional love and connection to all that is while sard by itself keeps one in the state of emotional attachments to family, home, their roots (the good memories of childhood) it also assist in digestion of proteins both animal and vegetable.
~forum post from whitehorse woman
Draws out NegativityOne of the main compounds of the Turquoise stone is copper. This is what gives it the blue, green, blueish-green colors. It also is often combined with the Azurite stone as well. Turquoise is wonderful for drawing out negative vibrations from a person. It is best to place it at the feet or worn inside the sock for this. It dissipates negativing as it draws from the body. It allows the negativity to go back into the ground. A good stone for helping one to bond with the spiritual. It offers much uplifting. Also helps open the heart chakra for giving and receiving.
HowliteSometimes dyed howlite is often mistaken for turquoise. And the howlite stone has more of the "black" lines than the actual turquoise stone. But by finding the copper traits in a piece of turquoise, it assures you of true turquoise. This stone does best with water cleansing and should not be cleansed with the sun. It should be kept out of the sun as much as possible. Carries the moon's energy or female energy. It is best set in the silver metals, also carrying the moon's energy.
~forum post from stones