Geology Home Page
Roger Weller, geology instructor
Chemical Group: silicate
Chemical Formula: (Mg,Fe)2SiO4
Color: olive green, white, brown, black Streak: white or gray
Luster: vitreous Transparency: transparent to translucent
Specific Gravity: 3.22 to 4.39
Cleavage: one direct, indistinct
Crystal Forms and Habits:
Olivine is commonly found in basalts as isolated crystals or granular xenoliths.
Uses: When transparent, green, and devoid of fractures, olivine is the gemstone peridot.
Arizona famous location- Peridot on the San Carlos Indian Reservation in
southern Arizona, about 80 miles east of Phoenix. The olivine occurs as granular masses
in a basalt flow perhaps 3 to 20 feet thick. The gemmy olivine is faceted in Germany and
Hong Kong to become the gemstone peridot.
2 miles North of Dish Hill which is 15 miles East of Ludlow on old route 666
between Needles and Barstow).
Portillo Maar and Kilbourne Hole, close to U.S./Mexico border, about 25 miles
Northwest of El Paso
Toxicity: when-swallowed- low when inhaled- high
Additional Information: Olivine is a mineral series that ranges from magnesium-rich (fayalite)
to iron-rich (forsterite).