( ( Because ( ( natural quartz ) ( is ( often twinned ) ) ) ) ( , ( ( synthetic quartz ) ( ( is ( produced ( for ( use ( in industry ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Because) (S (NP (JJ natural) (NN quartz)) (VP (VBZ is) (ADJP (RB often) (JJ twinned))))) (, ,) (NP (JJ synthetic) (NN quartz)) (VP (VBZ is) (VP (VBN produced) (PP (IN for) (NP (NP (NN use)) (PP (IN in) (NP (NN industry))))))) (. .)))
Because natural quartz is often twinned, synthetic quartz is produced for use in industry.
(ROOT (S (NP (DT The) (NN mineral) (NN quartz)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB produce) (NP (NN glass))))))) (. .)))