It is a type of green agate , composed mostly of silica and a small percentage of nickel .
This is perhaps the agate of Ex. , xxviii , 20 , and xxxix , 13 , since the chrysoprasus was not very well known among the ancients .
xxviii is a agate of green agate , composed mostly of silica and a small percentage of nickel .
This is perhaps the agate of Ex. , xxviii , 20 , and xxxix , 13 , since the chrysoprasus was not very well known among the ancients .