[ETL]

I just looked up opal on Wiki. It’s amorphous and has a similar hardness to glass, so does that mean it’s a naturally occurring glass?

Definition of glass

1: any of various amorphous materials formed from a melt by cooling to rigidity without crystallization: such as
a: a usually transparent or translucent material consisting typically of a mixture of silicates
b: a material (such as obsidian) produced by fast cooling of magma

https://www.merriam-webster.com/dictionary/glass
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Definition of opal

a usually amorphous mineral that is a hydrated silica softer and less dense than quartz and typically with definite and often marked iridescent play of colors and is used especially as a gem

https://www.merriam-webster.com/dictionary/opal

[Moonman62]

Thanks. Other than the hot melt for glass they seem similar.