WHy is quartzite harderand more resistant than it's parent rock (which is quartz and sandstone)???
Let qi = angle of incidence and qr = angle of refraction. Then Snell's Law is ni sin(qi) = nr sin(qr) If the light is coming from the air into the quartz then ni = 1 sin(qi) = nr sin(qr) ---> nr = sin(qi)/sin(qr) Plug and chug.
Snell's Law: n1 * sin(θ1) = n2 * sin(θ2) or sin (θ1) / sin (θ2) = n2 / n1 Since you do not specify, I need to make an assumption... Assume that the original medium is AIR. The quartz block could be underwater. In that case n1 would be n(water)=1.33. Calculating to 3 significant digits, n(air) = 1.00 n(quartz) = x sin (30.1°) / sin (20.3°) = x/1.00
