SB 3.26.39

द्रव्याकृतित्वं गुणता व्यक्तिसंस्थात्वमेव च ।
तेजस्त्वं तेजसः साध्वि रूपमात्रस्य वृत्तयः ॥३९॥

dravyākṛtitvaṁ guṇatā
vyakti-saṁsthātvam eva ca
tejastvaṁ tejasaḥ sādhvi
rūpa-mātrasya vṛttayaḥ

dravya—of an object; ākṛtitvam—dimension; guṇatā—quality; vyakti-saṁsthātvam—individuality; eva—also; ca—and; tejastvam—effulgence; tejasaḥ—of fire; sādhvi—O virtuous lady; rūpa-mātrasya—of the subtle element form; vṛttayaḥ—the characteristics.

My dear mother, the characteristics of form are understood by dimension, quality and individuality. The form of fire is appreciated by its effulgence.

Every form that we appreciate has its particular dimensions and characteristics. The quality of a particular object is appreciated by its utility. But the form of sound is independent. Forms which are invisible can be understood only by touch; that is the independent appreciation of invisible form. Visible forms are understood by analytical study of their constitution. The constitution of a certain object is appreciated by its internal action. For example, the form of salt is appreciated by the interaction of salty tastes, and the form of sugar is appreciated by the interaction of sweet tastes. Tastes and qualitative constitution are the basic principles in understanding the form of an object.