( ( A ( crystalline substance ) ) ( ( is ( ( any ( ( naturally occurring ) ( solid substance ) ) ) ( with ( a ( definite ( chemical composition ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ crystalline) (NN substance)) (VP (VBZ is) (NP (NP (DT any) (ADJP (RB naturally) (VBG occurring)) (JJ solid) (NN substance)) (PP (IN with) (NP (DT a) (JJ definite) (NN chemical) (NN composition))))) (. .)))
A crystalline substance is any naturally occurring solid substance with a definite chemical composition.
(ROOT (S (NP (NP (DT The) (NN majority)) (PP (IN of) (NP (NNS solids)))) (VP (VBP are) (VP (VBG crystalline) (PP (IN in) (NP (NN nature))))) (. .)))