Astral Travel Stones & Crystals
There are dozens of valuable and powerful stones that can be used to improve your astral projection practice. Here I will only cover the two most prominently used and why they are so thoroughly accepted as effective stones for this purpose.
Quartz Crystals

Without question, the dominant stone in the field of astral projection and spiritual advancement is the quartz crystal. Its powers in cleansing, amplifying, clarifying and guiding have been recognized for millennia. It is possible that the reason behind these remarkable and diverse properties could be that quartz has a piezoelectric effect. What this means is that quartz has an exceptional ability to both store and transmit energy. This is exactly why quartz is so prominently used in electronic devices today. (http://www.crystalvaults.com/crystal-encyclopedia/quartz).

These properties are ideal for astral projection for two very different reasons. Firstly, quartz acts as a spiritual sponge, absorbing and cleansing energy. Grasping a quartz firmly in your hand or applying pressure to the stone transmits energy from yourself to the stone. The purpose of this is to remove stress, worry, negativity and fear from yourself. Quartz has a purifying effect and can enable you to release anything that may hold you back from fully moving into a state of astral ascendance. The second benefit of using a quartz crystal in your astral rituals is that it can intensify your vibrations. This is key to astral projection. Another important reason to consider using quartz for astral travel is that quartz is associated with the Crown Chakra in Ayurveda practices. The Crown Chakra is the seat of heaven and houses the cosmic soul. This stone vibrates at a similar level as our spiritual, ethereal bodies and can connect with this aspect of the self.
Amethyst

Amethyst is associated with both the Third Eye and the Crown Chakra. The Third Eye helps us gain spiritual sight. It enables us to look more deeply into and out of our selves.Amethyst gains its pulchritudinous lavender color from minuscule impurities of Iron in the structure of the crystal. It is important to note that amethyst is actually a type of quartz crystal. (http://www.minerals.net/mineral/amethyst.aspx) This addition of iron links amethyst to our very blood. It vibrates with the same intensity as a true quartz but is more “human” and more grounding. Where pure quartz crystal aids us in transcending ourselves, amethyst helps us to better understand the being we are attempting to transcend.
Tips for Working With Your Stones

There are stones associated with each of the main chakras of the body. If you suffer from ailments, sickness of the spirit or general imbalances then it is recommended that you find the stone associated with your suffering and meditate on cleansing and purifying that aspect of yourself.
Choose a stone that is free of inclusions unless the inclusions call to you. An inclusion is a disruption within the stone itself. If the stone is not perfectly clear and demonstrates what appears to be internal cracks, fogginess, or even another type of mineral then these are considered inclusions. Some inclusions can be beautiful and, therefore, if you feel drawn to the design or effect of an inclusion do not shy away from using the stone.
Choose a stone that is free of inclusions unless the inclusions call to you. An inclusion is a disruption within the stone itself. If the stone is not perfectly clear and demonstrates what appears to be internal cracks, fogginess, or even another type of mineral then these are considered inclusions. Some inclusions can be beautiful and, therefore, if you feel drawn to the design or effect of an inclusion do not shy away from using the stone.

If you use a stone for purifying purposes then it is good to set the stone in a bowl of salt to remove the negative energy. Salt’s negative ions attract energy. In this way, the salt will remove the energy you have given up to the stone. You can then toss the salt and you have a fresh, new stone to work with.
If you do not wish to cleanse your stone then avoid handling it while in a bad mood, sad or angry. Only use it when you are prepared to amplify the energy that you represent.
If you do not wish to cleanse your stone then avoid handling it while in a bad mood, sad or angry. Only use it when you are prepared to amplify the energy that you represent.