Realgar
An orange-red arsenic sulfide mineral once used as a pigment and poison
No single value: Realgar is a material, and its colour varies. The background shows its family, red.
Realgar is a soft, orange-red mineral made of arsenic and sulfur, found in crystals or powder. Its name comes from Arabic for 'powder of the mine'. Realgar was used as a pigment in art, as a poison, and in fireworks, but is toxic and breaks down in light.
- Realgar is an orange-red arsenic sulfide mineral
- It was used as a pigment in art and fireworks
- Exposure to light turns it into yellow pararealgar
- Realgar is toxic and carcinogenic
- Its name comes from Arabic for 'powder of the mine'
What colour is Realgar?
Realgar is a mineral that appears in shades from orange-red to yellow-orange. It forms soft, prismatic crystals or can be found as a powder or in compact masses. Its streak is red-orange to red, and it has a resinous or greasy shine. Realgar stands out for its vivid colour and its tendency to break down into a yellow powder when exposed to light, which sets it apart from similar minerals like orpiment.
Where does Realgar come from?
The word 'realgar' comes from the Arabic phrase for 'powder of the mine', passing through Medieval Latin before entering English in the 1390s. The mineral has been known since ancient times, traded in the Roman Empire, and used in various regions including China, India, Central Asia, and Egypt. Its Chinese name, xiónghuáng, means 'masculine yellow', in contrast to orpiment, 'feminine yellow'.
How is Realgar made?
Realgar is a naturally occurring mineral made of arsenic and sulfur, with the formula As4S4. It is found in low-temperature hydrothermal veins, volcanic areas, and hot springs, often alongside minerals like orpiment and arsenolite. Over time, exposure to light turns realgar into a yellow powder called pararealgar.
Where Realgar is used
In the past, realgar was used as a red pigment in painting, especially in China, India, Central Asia, Egypt, and Renaissance Venice. It was also used in fireworks for white flames and yellow smoke, in traditional medicine, and to poison pests. Other uses included dyeing cloth, printing, and making lead shot. Its use in art faded by the 18th century.
Red around the world
What the red family means from country to country.
Red stands for good fortune and happiness. Brides traditionally wear it, doors are hung with red couplets at New Year, and gifts of money come in red envelopes.
Luck and prosperityFestival and celebrationWeddings and marriageJoySource: Color in Chinese cultureThe national flag is red with five yellow stars. The red stands for the Communist revolution, and the same red runs through party banners and slogans.
Politics and protestPrideSource: Flag of ChinaThe ancient Egyptians called the desert deshret, the red land. Red was the colour of the god Set, of chaos and of danger, and scribes wrote unlucky words in red ink.
Danger and warningFearSource: RedThe flag is red, white and black. Red recalls the struggle before the 1952 revolution, white the revolution itself, which was nearly bloodless, and black the end of oppression.
Politics and protestPrideSource: Flag of EgyptThe flag is red, white and green: red for strength, white for faithfulness and green for hope. On 15 March people pin on a cockade in the three colours.
Politics and protestPrideSource: Flag of HungaryOn Easter Monday boys sprinkle girls with water or perfume and are given painted eggs in return. The classic egg is plain red, piros tojas.
Festival and celebrationLove and desireSource: Easter eggShades and relatives of Realgar
Realgar is closely related to orpiment, another arsenic sulfide mineral, but is more red-orange while orpiment is yellow. When exposed to light, realgar changes into pararealgar, a yellow powder. It is also trimorphous, meaning it shares its chemical formula with pararealgar and bonazziite but has a different structure.
Questions people ask about Realgar
What colour is realgar?
Realgar is orange-red to yellow-orange, with a red-orange to red streak. In polished form, it can show pale grey with yellow to red reflections.
Where does the name 'realgar' come from?
The name comes from the Arabic 'rahj al-ġār', meaning 'powder of the mine', and entered English in the 1390s.
What was realgar used for?
Realgar was used as a pigment in art, in fireworks, as a poison for pests, in medicine, and in dyeing and printing.
Is realgar safe to use?
No, realgar is toxic and carcinogenic. It releases arsenic fumes when burned and breaks down into other arsenic compounds in light.
What happens to realgar when exposed to light?
It changes into a yellow powder called pararealgar, which is a different chemical compound.
Good reading and sources
The facts on this page come from the Wikipedia article "Realgar", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). Rang rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes. The swatch is an approximation: named colours are not fixed standards, and every screen shows them a little differently. If something is wrong, tell us. Last refreshed 2026-10-03.
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