The most important aspect of this video is how Australian opal REALLY forms. The old theories are incorrect!
The digit pattern in precious opal, particularly notable in Australian opal, is a rare and striking phenomenon characterized by fingerlike structures within the gemstone. These structures, resembling fingers or digits, were first documented in a 2013 article in Gems and Gemology by French authors, Rondeau, et al, who termed it the "digit" pattern.
Justin Thomas of Black Opal Direct notably discovered a large example of this pattern, named the "Rainbow Serpent," in 2016. While this digit pattern is more commonly observed in Ethiopian opal, its occurrence in Australian opal is relatively scarce. The formation of these fingerlike structures, termed prismatic photonic colloidal crystals by Australian gemologists, is believed to be the fundamental process behind all precious opal formation.
This digit pattern is the natural way that all precious opal forms and this is exemplified the creation of synthetic opal, in which the digit pattern forms naturally. The intricate process of opal formation involves the deposition of colloidal silica within sedimentary rock, resulting in the formation of columns of opal that are often disrupted by subsequent silica flows. However, some opal seams, such as those found in Coober Pedy and Andamooka, manage to preserve the delicate columnar structures, contributing to their beautiy, rarity and value.

Link to Black Opal Direct's Video of the Amazing Black Digit opal, the Rainbow Serpent:

   • One of the rarest opals on the planet...  

Links to Videos on How to make Opal:

   • Making Opals for Free Air Conditioning  

   • Can you GROW an Opal?