Agate Photos
Cochise College                                                                                                                      
Photos of Gemstones
Translucent Gemstones

Geology Home Page
Roger Weller, geology instructor               

Montana agate

last edited:  2/16/18   number of photos: 163                                                   
Agate is a cryptocrystalline form of quartz, SiO2
Mineral information on quartz
Moss agate contains dendrites (tree-like inclusions) made of pyrolusite (manganese oxide)
or iron oxides.
Quartz onyx is actually agate with straight, flat layers.
The banded nature of agate is due to atoms migrating through a silica gel, one layer at a time.
Later the silica gel crystallines to extremely tiny fibrous crystals of quartz.

lectures on agate
Agate by Audrey La Clair

reference on agates
I am highly recommending the following book on agates.
Agates Inside Out  by Karen A. Brzys, 2010, 246 pages
only available from Gitche Gumee Agate and History Museum

P.O. Box 308, Grand Marais, Michigan (MI) 49839
(906) 494-2590   or
outstanding colorful photos and scientific explanations

agate from India:  A

agatized coral:  A  B  C

banded agate:  A
black agate: 

blue lace agate:  A
crazy lace agate: 
A  B  C  D  E  F  G  H I  J  K  L 
          M  N  O  P  Q  R

dendritic agate:  A  B  C  D E  F G  H  I  J 
fire agates: 
A  B  C  D
Laguna agate: 
Montana agate: 
A  B  C

moss agate, faceted:  A  B                                                      
moss agate cabochons:  A  B

mixed colors:  A                                                                           
sagenitic agate: 
A  B  C  D  E  F G                                              
turritella agate: 
A  B


agates in jewelry

carnelian pendants:  A

fire agate rings:  A

banded agate beads:  A

blue agate beads:  A  B 
agate beads:  A


agate, uncut

African banded agate:  A
agate banding, close up: 
A  B

agate with pink center:  A  B
amethyst sage agate: 

banded agate:  A  B  C D  E  F  G H  I  J  K  L 
   M  N  O  P  Q  R  S 
blue agate:  A
Botswana agate: 
A  B                                                                                                       

Brazilian agates:  A  B C  D  E  F  G  H  I  J  K  L 
          M  N
  O  P  Q  R  S  T  U  V  W  X  Y 

carnelian:  A

chalcedony:  A

crazy lace agate:  A  B  C  D  E
dendritic agate:  A  B

eye agate:  A  B
fire agate:  A  B  C  D

Lake Superior agate:  A  B  C  D  E  F  G  H  I  J  K

Montana agate:  A  B  C  D  E  F  G  H I  J K*
moss agates:  A  B  C

red, white and blue agate:  A

Texas agate:  A

thundereggs:  A  B  C  D  E  F  G

tumble polished agates:  A

white agate:  A  B


Photos are copyright free for non-commercial educational uses. 
Just credit photos to R.Weller/Cochise College.
copyright 2018-R.Weller