This article aims to identify the basic geometric structures found in the illumination of the Terengganu Quran Manuscript (L.M.N.T 2002.1) collection. The study focuses on the appreciation of art, employing a formalistic approach to visually examine the evident basic geometric structures present in the illumination of the Quran Manuscript (L.M.N.T 2002.1). The research methodology involved observing the illumination of the Quran Manuscript (L.M.N.T 2002.1) and analysing the basic geometric structures based on formalistic aspects such as elements of art and principles of design through formalistic visual analysis using Adobe Illustrator software. In general, the illumination image displays the shape of a rosette or medallion. This character is also viewed from the perspective of cosmology, whereby it is a resemblance of a glowing star and the shining sun. This is appropriate with the concept of lighting or Shamsa. The findings of this research indicated some views on basic geometry in the illumination of the Quran Manuscript (L.M.N.T 2002.1) as an introduction to new knowledge in the field of art in general.