How to identify the nature of amphibolite lenses within the marble? No alteration is observed along the boundary, except a thin dark coloured zone (baked margin?) along the amphibolite. At places, the amphibolite varies in the range of less than a cm to tens of cms. calcite lens are preserved within the larger amphibolite lenses.

I am not clear what you mean by asking about "the nature of the amphibolite lenses".

 

I don't think you mean identifying their mineralogy, since by describing the lenses as being amphibolite you must have noted their mineral composition.

 

I don't think you mean the structural character of the lenses, since you have also described that.

 

I don't think you mean the origin of the lenses, since - given the context of lenses in marble - that is likely prograde amphibolite facies metamorphism of a dolomite, or limestone with interbedded clays and marls.

 

So, what am I missing?