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Table 1 Classification of garnet on the basis of chemistry and inclusion/lamella phases

From: Hydrous Na-garnet from Garnet Ridge; products of mantle metasomatism underneath the Colorado Plateau

  

Chemistry

Exsolution lamella phases

Garnet group

Color

Prp (mol%)

Alm (mol%)

Grs (mol%)

Cr2O3 (wt.%)

Cpx

Amp

Ap

Rt

Ilm

Ctn

Sri

Crm

Cr-Spl

 A. Cr-rich pyrope

Red-purple

67–74

13–18

7–11

1.0–6.4

   

+

+

+

+

+

+

 B. Cr-poor pyrope

              

  B1. Amp type

Brown

49–66

18–28

16–26

<0.4

 

++

+

++

++

+

+

  

  B2. Ilm-only type

R-brown

49–68

20–38

12–19

0.4–2.0

    

++

   

+

  B3. Dense lamellae type

Black

54–72

18–33

12–15

<1.0

++

++

+

++

++

 

+

  

  B4. Cpx-Amp type

Light brown

61–76

13–27

6–11

<0.6

++

+

 

++

++

    
 

Inclusions without lamella textures

Garnet group

Ol

Opx

Cpx

Ti-Chu

Chl

Spl

Crn

Dol

Mgs

Ap

sulfides

Multi

  

 A. Cr-rich pyrope

++

++

++

+

+

+

    

+

+a

  

 B. Cr-poor pyrope

              

  B1. Amp type

  

++

 

+

  

+

+

+

+

   

  B2. Ilm-only type

++

++

++

 

+

    

+

+

++b

  

  B3. Dense lamellae type

  

++

  

+

+

  

+

+

++c

  

  B4. Cpx-Amp type

+

+

        

+

   
  1. Ap apatite, Ctn crichtonite, Sri srilankite, Crn carmichaelite, Cr-Spl chromian spinel, Ti-Chu titanian clinohumite, Crn corundum, Dol dolomite, Mgs magnesite
  2. aMulti phase inclusions composed of Dol, Mgs, Amp, Phl, Rt, Ap, Cr-Spl, and sulfides
  3. bMulti phase inclusion composed of gas, liquid-H2O, and solid phases (rutile, chlorite, calcite, and barite)
  4. cMulti phase inclusion composed of Dol, Mgs, Amp, Cpx, Opx, Ab, Ap, Rt, Ilm, and sulfides