In the formation of snow, nature shows us in statu agendi a process which we otherwise meet in the earth only in its finished results, crystallization. We may, therefore, rightly look upon snow-formation as an ur-phenomenon in this sphere of nature's activities. As such it allows us to learn something concerning the origin in general of the crystalline realm of the earth; and, vice versa, our insight into the 'becoming' of this realm will enable us to see more clearly the universal function of which phosphorus is the main representative among the physical substances of the earth. It has puzzled many an observer that crystals occur in the earth with directions of their main axes entirely independent of the direction of the earthly pull of gravity. Plate VI shows the photograph of a cluster of Calcite crystals as an example of this phenomenon. It tells us that gravity can have no effect on the formation of the crystal itself. This riddle is solved by the phenomenon of snow-formation provided we allow it to speak to us as an ur-phenomenon. For it then tells us that matter must be in a state of transition from lightness into heaviness if it is to appear in crystalline form. The crystals in the earth, therefore, must have originated at a time when the relation between levity and gravity on the earth was different from what it is, in this sphere, to-day. The same language is spoken by the property of transparency which is so predominant among crystals. One of the fundamental characteristics of heavy solid matter is to resist light - in other words, to be opaque. Exposed to heat, however, physical substance loses this feature to the extent that at the border of its ponderability all matter becomes pervious to light. Now, in the transparent crystal matter retains this kinship to light even in its solid state. A similar message comes from the, often so mysterious, colouring of the crystals. Here again nature offers us an instance which, 'worth a thousand', reveals a secret that would otherwise remain veiled. We refer to the pink crystals of tourmaline, whose colour comes from a small admixture of lithium. This element, which belongs to the group of the alkaline metals, does not form coloured salts (a property only shown by the heavier metals). If exposed to a flame, however, it endows it with a definite colour which is the same as that of the lithium-coloured tourmaline. Read as a letter in nature's script, this fact tells us that precious stones with their flame-like colours are characterized by having kept something of the nature that was theirs before they coalesced into ponderable existence. In fact, they are 'frozen flames'. It is this fact, known from ancient intuitive experience, which prompted man of old to attribute particular spiritual significance to the various precious stones of the earth and to use them correspondingly in his rituals.