This was also a crystal stone, except it had turned pale gold, and its interior could no longer be seen clearly.
Yet the white light did not stop. It continued extending downward and soon reached the fourth pattern.
Another image appeared. It depicted a pure golden crystal stone, its surface covered in countless tiny holes. Faintly, one could see strands of golden force, as fine as cowhair, shooting out from those holes.
Merely looking at the image gave one a piercing sensation.
Only then did the white light slowly disperse, no longer extending downward.
By now, Ning Fa was somewhat dumbfounded.
His gaze swept back and forth across the four images. When he looked at the bottom two in particular, he could barely conceal his shock.
"Gold Thread Stone, Radiant Gold Stone, Geng Metal, Gold Source Crystal Core..."
Ning Fa murmured excitedly.
The Radiant Gold Stone aside, though rare, was only a third-grade material.
But Geng Metal was a renowned treasure of sharp gold. Even among fourth-grade spiritual materials, it ranked among the very best.
The Gold Source Crystal Core was actually less famous than Geng Metal.
This was not because it was inferior to Geng Metal, but because it was a genuine fifth-grade spiritual material, and thus was not widely circulated in the cultivation world.
Even for Nascent Soul Cultivators, obtaining such a supreme spiritual material could only be a dream.
Now that the Source-Crossing Heavenly Book had revealed images of these four crystal stones, its meaning could not have been clearer.
It could use this second-grade Gold Thread Stone to trace its origin all the way back through the other three crystal stones.
The reason for this was evidently that these four crystal stones came from the same source. Their original source was very likely this Gold Source