Garnet Hill: Almandine vs. Spessartine

Hi all.
I would like to know if anyone knows exactly what kind of garnets (Almandine or Spessartine) are typical from Garnet Hill, Nevada.
Anybody knows the chemical composition?
Thank you very much and sorry for my English, and from Spain.

Angel,

From Minerals of Nevada, 2004, the garnet at Garnet Hill is 69.3% almandine and 28.5% spessartine. The difference fromm 100% is not addressed.

Doug

Thank you very much Doug

Garnets form a solid solution series, and can have a composition that is a mixture of different garnet end-member types. For example, almandine is an Fe-Al garnet, and spessartine is a Mn-Al garnet. The garnet you describe will have a composition that includes Fe, Mn and Al. When you add the percentages together, you should get close to 100%.

Google "garnet ternary diagram almandine spessartine" then look for "Minerals: Their Constitution and Origin - Google Books Result." You'll find a ternary diagram that shows the occurrence of mixtures.



Edited 1 time(s). Last edit at 05/13/2008 12:15PM by Fred E. Davis.