Hawk's eye
Variety SiO2
Also called Falcon's eye and Blue tiger's eye
Take care.
- Can shed asbestos fibres: Keep it in a closed box, and never break, saw, sand, or scrape it.
About it
Blue-grey chatoyant quartz in which the crocidolite fibres kept their blue colour instead of turning golden as in tiger's eye. From South Africa; safe once polished, but cut and grind it wet.
- Type
- Variety
- Group
- Quartz variety
- Formula
- SiO2
- Hardness (Mohs)
- 6.5–7
- Specific gravity
- 2.64–2.71
- Streak
- white
- Lustre
- silky, vitreous (glassy)
- Crystal system
- Trigonal
- Colours
- blue-grey, greenish blue, dark blue
- Transparency
- opaque
- Cleavage and fracture
- none; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.