It looks like a white liquid compound. It is made from all different types of flora, which likely gave it it's plain, white color.
Data Bank Entry
In a normal life cycle it seems emperor specimens would have buried their eggs in much shallower waters, where different organic materials in the soil would have triggered a hatching response.
By combining flora from the emperor's nesting regions with a hatching enzyme from the parent itself it should be possible to fabricate a substance which would synthesize the natural environment and catalyze the birthing process.