We Majiang JGL Barite Mine is a reliable manufacturer of natural barium sulfate in China. yuensons AT yahoo DOT COM whiteness: 88%-93% BaSO4 content: 96%-98% S.G.: 4.2-4.4 pH: 7-8 Si: max. 0.5%,Sr: max. 0.6%,CaO: 0.8-2% If you have related inquiry, pls feel free to contact us. Thank you. Yours sincerely/ VIvian