Why are some carts darker than others?

Both of these carts are live resin, both brand new not smoked. Why is one liquid darker than the other? I notice that with some carts. Is it age? Strain? What does this?

Both of these carts are live resin, both brand new not smoked. Why is one liquid darker than the other? I notice that with some carts. Is it age? Strain? What does this?