Wikipedia entity: Mineral
Topics: geology; minerals; composition
Original sentence: Pyroxenes are common in the Earth's crust (about 10%) and are a key constituent of mafic igneous rocks.Amphiboles have great variability in chemistry, described variously as a "mineralogical garbage can" or a "mineralogical shark swimming a sea of elements".
Quantified sentence: Pyroxenes are common in the Earth's crust (in small amounts)  and are a key constituent of mafic igneous rocks.Amphiboles have great variability in chemistry, described variously as a "mineralogical garbage can" or a "mineralogical shark swimming a sea of elements".
Quantifier: small
Percentage: 10%
Specificity: unable