淀粉样变性心肌经刚果红染色。淀粉样物质经染色后应为橙红色，但是在偏振光下，淀粉样物质如图所示为“苹果绿”双折射
A Congo red stain has been performed on the myocardium in a case of amyloidosis. The amyloid stains orange-red, but with polarized light, the amyloid has an "apple-green" birefringence as seen here.