Diamonds are graded from D to X, with only D, E, and F considered good, D being colorless or  river white,  J  slightly tinted,  Q  light yellow,  and S to X  yellow.  
( Diamonds ( ( are ( ( ( ( graded ( from D ) ) ( to X ) ) , ) ( with ( ( ( ( only ( ( D ( , ( E ( , ( and F ) ) ) ) ) ( considered ( ( ( ( good ( , ( D ( being colorless ) ) ) ) or ) ( river ( ( white ( , ( J ( slightly ( tinted , ) ) ) ) ) ( Q light ) ) ) ) yellow ) ) ) ) , ) and ) ( ( S ( to X ) ) yellow ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Diamonds)) (VP (VBP are) (VP (VBN graded) (PP (IN from) (NP (NNP D))) (PP (TO to) (NP (NNP X))) (, ,) (PP (IN with) (S (S (ADVP (RB only)) (NP (NNP D) (, ,) (NNP E) (, ,) (CC and) (NNP F)) (VP (VBD considered) (S (NP (NP (JJ good) (, ,) (JJ D) (JJ being) (NNS colorless)) (CC or) (NP (NN river) (ADJP (JJ white) (, ,) (IN J) (RB slightly) (JJ tinted) (, ,)) (NNP Q) (NN light))) (ADJP (JJ yellow))))) (, ,) (CC and) (S (NP (NP (NNP S)) (PP (TO to) (NP (NNP X)))) (ADJP (JJ yellow))))))) (. .)))
The most expensive diamonds on the planet are graded with D.
( ( ( The ( ( most expensive ) diamonds ) ) ( on ( the planet ) ) ) ( are ( graded ( with D. ) ) ) )
(ROOT (S (NP (NP (DT The) (ADJP (RBS most) (JJ expensive)) (NNS diamonds)) (PP (IN on) (NP (DT the) (NN planet)))) (VP (VBP are) (VP (VBN graded) (PP (IN with) (NP (NNP D.)))))))