This study sought to explore the advanced lexicon, one of the hallmarks of text quality. To this end, we analysed the advanced lexicon deployed in the production of two types of texts -- a descriptive and an argumentative -- by Hebrew-speaking school children. Our study had two goals, the first to trace the developmental path of the use of advanced lexicon in writing scholastic types of texts. The second goal was to investigate the relations between literacy-related abilities and the use of advanced lexicon in writing. Accordingly, 292 Israeli grade-school children (second-, third-, fourth- and fifth-graders) were administered a linguistic, cognitive, reading and spelling test battery and produced two descriptive and two argumentative texts. The texts were analysed for noun abstractness, occurrence of internal-state verbs and the morphological complexity of adjectives. Findings showed an age-related increase in both literacy-related abilities and the lexical quality in the texts. Moreover, interactions found between lexical quality, age and genre suggest that text quality is dynamic, determined by a network of differential age- and literacy-related factors. [Translation from English by Mercè Rius.]