菱铁矿与硬石膏的鉴别:将0.1克茜素红S溶于100毫升的0.2%盐酸溶液中,用棕色瓶保存备用.鉴定时先将试样用5%盐酸浸泡2分钟.在200毫升的烧杯中注入制备的茜素红S溶液约3毫升、30%的NaOH溶液约2毫升;投入试样,使光面与杯底接触、压紧,用酒精灯煮沸;约2分钟,试剂煮净,并使试样与杯底保持潮湿;取出试样立即投入室温净水中洗净.菱铁矿染成深褐至黑色,硬石膏不染色.本法适用用光片及手标本碎块. Siderite and anhydrite identification: 0.1 g of alizarin red S dissolved in 100 ml of 0.2% hydrochloric acid solution, stored in brown bottles for future use first sample was soaked with 5% hydrochloric acid for 2 minutes in 200 ml About 3 ml of Alizarin Red S solution and about 2 ml of 30% NaOH solution were injected into a beaker. The sample was put in to bring the smooth surface into contact with the bottom of the cup and squeezed to boil with an alcohol lamp. After about 2 minutes, Net, and keep the sample and the bottom of the cup moist; remove the sample immediately into the room temperature water purification wash siderite dark brown to black, anhydrite is not stained. .