Which reagent identifies calcium?

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Multiple Choice

Which reagent identifies calcium?

Calcium in tissue is identified by staining its mineral salts, not the element itself. The classic method uses silver nitrate in the Von Kossa stain. In areas where calcium is present as phosphate or carbonate, the silver ions react to form silver phosphate or silver carbonate, which is then reduced by light to metallic silver. This produces a dark (black/brown) deposit precisely where calcification has occurred, highlighting calcium-containing areas. Other reagents here target different tissue components: osmium tetroxide fixes and stains lipids, while Hall’s Fouchet solution is used for pigments such as bile pigments, and Schmorl’s reagent serves other staining purposes. Because only Von Kossa marks calcium-containing mineral deposits, it’s the best choice for identifying calcium.

Calcium in tissue is identified by staining its mineral salts, not the element itself. The classic method uses silver nitrate in the Von Kossa stain. In areas where calcium is present as phosphate or carbonate, the silver ions react to form silver phosphate or silver carbonate, which is then reduced by light to metallic silver. This produces a dark (black/brown) deposit precisely where calcification has occurred, highlighting calcium-containing areas.

Other reagents here target different tissue components: osmium tetroxide fixes and stains lipids, while Hall’s Fouchet solution is used for pigments such as bile pigments, and Schmorl’s reagent serves other staining purposes. Because only Von Kossa marks calcium-containing mineral deposits, it’s the best choice for identifying calcium.

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