Embolism. Pulmonary emboli were formed by blue-purple particles (A: hematoxylin and eosin stain, ×40) and showed birefringent crystals characteristic (B: polarized light, ×40). Von Kossa staining proved the emboli to be calcium salt (C: Von Kossa stain, ×40). Massive Pulmonary Calculi Embolism: A Novel Complication of Pneumatic Lithotripsy: A Case Report. Zhang L, Zhou Y - Medicine (2015). Not Altered. CC.