( ( Although ( color ( is ( ( the ( ( most obvious ) property ) ) ( of ( a mineral ) ) ) ) ) ) ( , ( it ( ( is ( the ( ( least reliable ) ( diagnostic ( physical property ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Although) (S (NP (NN color)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ obvious)) (NN property)) (PP (IN of) (NP (DT a) (NN mineral))))))) (, ,) (NP (PRP it)) (VP (VBZ is) (NP (DT the) (ADJP (JJS least) (JJ reliable)) (NP (JJ diagnostic) (JJ physical) (NN property)))) (. .)))
Although color is the most obvious property of a mineral, it is the least reliable diagnostic physical property.
(ROOT (S (SBAR (IN Although) (S (NP (PRP it)) (VP (VBZ is) (NP (DT the) (JJS easiest) (S (VP (TO to) (VP (VB observe)))))))) (, ,) (NP (NN color)) (VP (VBZ is) (RB not) (ADJP (JJ ideal) (PP (IN as) (NP (DT a) (JJ sole) (NN way)))) (S (VP (TO to) (VP (VB identify) (NP (NNS minerals)))))) (. .)))