Within the depth-psychology corpus, glass occupies a remarkably dense symbolic field that cuts across alchemy, fairy tale, dream analysis, and philosophy of consciousness. Its primary valence is epistemological: glass is the substance of transparency, that which permits vision while itself remaining invisible — a paradox that Jung’s Mysterium Coniunctionis exploits when associating glass with the glorified body, incorruptibility, and the purifying power of salt and fire. Edinger develops this line most systematically, cataloguing glass artifacts — vessels, windows, mirrors, telescopes — as instruments of extended or contained vision, and noting the violence latent in the image: broken glass lacerates. Von Franz introduces the crucial counter-note, identifying glass as the material of cold intellect: it transmits sight but not warmth, perception but not feeling, making the glass coffin of Snow White an image of consciousness severed from life. Hillman, working through alchemical texts, reads the glass vessel functionally: its clarity enables the alchemist to witness internal transformation, its thickness protects the embryonic work, its breaking signals catastrophic premature release. Abraham’s dictionary confirms the glass as the canonical alchemical retort — the ‘glass prison’ in which sulphur and mercury are sealed for the coniunctio. Across these positions runs a productive tension: glass as the ideal medium of reflective consciousness versus glass as the cold barrier that arrests embodied relatedness.