measured	value	unit
[SiO₂]	47.2	%
[Al₂O₃]	36.5	%
[Cr₂O₃]	1.53	%
[MgO]	0.41	%
[Na₂O]	0.41	%
[K₂O]	8.21	%
[BaO]	1.16	%
[B₂O₃]	1378.0	µg/g

tables:

Table 2. Chemical compositions of mica. With the exception of boron, abundances of elements are normalized to a total of 100cg/g of Ota, Tsutomu (2019) Tourmaline in a Mesoarchean pelagic hydrothermal system: Implications for the habitat of early life, Precambrian Research, 334. more