The volume of quartz will be given by the increase in volume which is 25.7 - 18.3 =7.4 ml.
1) Graduated cylinder has 18.3 mL - initial volume
2) After placing a quartz in the graduated cylinder, the volume rises to 25.7 mL - final volume
THE FINAL ANSWER IS 7.4 mL.
(Volume final - Volume initial = Volume of the quartz)
25.7 mL - 18.3 mL = 7.4 mL - volume of the Quartz