measured	value	unit
[SiO₂]	36.8	%
[TiO₂]	0.83	%
[Al₂O₃]	30.6	%
[FeO^T]	10.3	%
[MgO]	4.94	%
[Na₂O]	2.27	%

tables:

Table 1-1. Chemical compositions of tourmaline.Elemental abundances are normalized to a total of 100 cg/g of Ota, Tsutomu (2019) Tourmaline in a Mesoarchean pelagic hydrothermal system: Implications for the habitat of early life, Precambrian Research, 334. more