The garnet-group
The garnet-group is a family of complex euhedral minerals (minerals with the same crystal structure).  
All garnets have a cubic  crystal structure and a hardness about  6,5 - 7. 
The indiviual mineral species: 
    Pyrope             A brownish-red, dark gem  that occurs in  Madagascar, Burma und Russia. 

    Rhodolite       A rose-red mixture of the two minerals pyrope und almandine from Kenya und Sambia. 

    Almandine      Blood-red to violet gem from India, Sri Lanka und Sambia. 

    Spessartite     A brownish-red to orange gem from Sri Lanka, Burma and Madagascar. 
     
     

           
    Grossular      Yellowish-green to green gem. 
                           Some mineral species that belong
          to grossular: 
          Hessonite brownish-red to brownish-yellow gem. 
          Tsavolite  Yellow to pinkish-brown.  
          Opake grossular A dense, opake aggrgate that looks very similar to jade and is often  mixed up with it. 
           
    Andradite       An ordinary andradite
          is yellowish-brown
          to brown, some mineral
          species have even different colours:
          Demantoid Its dark, green colour is caused by chromium and it is very longing due to his high refractive index. 

          Topazolite   A lemon-yellow garnet. 

          Melanite     A completly black mineral species that is often used for funeral-jewellery. 

          Uwarovite      Coloured green due to traces of chromium, but also its high refractive index make it very longing.