Crocidolite, (blue asbestos,) alters to quartz, but while retaining its fibrous structure. This material is frequently stained by iron, giving it a golden brown color. We know this material as tiger's eye. Unstained pieces, retaining their original blue color, are called Hawk’s Eye. There are also pieces with both colors.
Metaphysical Properties of Tiger's Eye - Gold: Solar Plexus Chakra, Confidence, Willpower, Strength, Optimism, Integrity, Self-worth, Grounding, Energising, Protection, Balance