The sand usually used to make glass contains natural impurities of iron, which gives the glass a green tint.
(iron; gives; the glass; a green tint) (The sand; to make; glass contains natural impurities of iron) Context(The sand to make,List([0, 29))):(glass; contains; natural impurities of iron)
The sand to make,List([0, 29))
iron The sand glass
gives to make contains
the glass a green tint
glass contains natural impurities of iron
natural impurities of iron