Assertion: obsidian's impurity | /r/CapableOf | produce green tint
Facets:
Source sentences:
text: Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments.