today we will unveil the mystery of cinnabar and learn how to distinguish the authenticity of this ancient mineral. Cinnabar, also known as mercury sulfide (HgS), is a mineral with a long history, known for its bright red color and unique properties. But when collecting and using cinnabar, how can we ensure that what we have is the real deal and not a counterfeit? Here are some key identification tips.
Authentic Cinnabar Characteristics:
- Appearance: Genuine cinnabar is a granular or blocky aggregate, appearing in granular or blocky pieces, with colors ranging from bright red to dark red, and streaks from red to brownish-red, with a luster.
- Texture: Heavy weight, brittle, blocky pieces are easily broken, and powdery pieces have a shimmering luster.
- Odor: Odorless and tasteless.
- Solubility: Insoluble in water, nitric acid, and sulfuric acid, but soluble in aqua regia and sodium sulfide solution.
Types of Cinnabar:
- Bean Cinnabar: Blocky, larger, with a dark or grayish-black color.
- Rice Cinnabar: Smaller particles.
- Mirror Cinnabar: Slanted square or elongated rectangular pieces, with a bright red color, shiny like a mirror, and slightly transparent.
- Artificial Cinnabar: Synthetically produced cinnabar.
Counterfeit Cinnabar Characteristics:
- Appearance: Powdery, dark brownish-red, with a few regular granules, granules have a luster, heavy weight, and hard texture.
- Odor: Odorless and tasteless.
- Heating Reaction: The color quickly fades to a silver-gray powder when heated directly by fire.
- Solubility: When ground in water, the granules are not easily crushed, and the suspension is dark brown.
Adulterated Cinnabar Characteristics:
- Appearance: Often granular or arc-shaped and broken, with a brownish-red surface, no metallic luster.
- Texture: Heavy weight, hard texture, not easily broken, and the cross-section shows a layered texture.
Counterfeit Identification Methods:
- Hematite: Mainly contains iron(III) oxide (Fe2O3), soluble in strong acids, the powder plus hydrochloric acid solution turns blood-red with potassium thiocyanate.
- Slag, Sand Grains: Dyed and can color water when washed, while the red color of slag and sand grains becomes lighter or fades.
- Dark Red Ore: The variety is to be determined, insoluble in water, some soluble in strong acids.
By using these characteristics, we can accurately identify the authenticity of cinnabar. When collecting and using cinnabar, be cautious to ensure that what we have is genuine cinnabar to maximize its value and function.