Statistically significant correlations (generally at the 99 + % level of significance) were observed only between variable pairs that are indicative of the oxy-component. Namely, there is an inverse correlation between the univalent anion content of the O3 site (i.e., OH + F + Cl) and both Fe3+ and Ti contents, an inverse correlation between Al3+ and Ti, and a positive correlation between the amount of positive charge in excess of 46.0 per formula unit and both Fe3+ and Ti. The induced negative correlation that results from the fact that these are variables of a constant sum could lower the statistical significance of the inverse correlations but would increase the significance level of the positive correlations. A statistically significant correlation was not observed among any of the variables related to the accommodation of Fe3+ by the Al-substitution mechanism. It is concluded that the Fe3+-, Ti-, and OH contents in this population of amphiboles are controlled mainly by the coupled substitution mechanisms described in Equations 1 and 2.