An expert has solved a viral mystery after a woman's post about her mom's volcanic cooking pot sparked intrigue online by turning the stove flame green.
Reddit user Angelaw1215 shared a photo of the pot sitting on a gas stove, where the flame had changed to a green hue. The post, shared in the thread "mildly interesting," quickly garnered 60,000 upvotes.
"My mother is making sauce in a mortar made with volcanic rock and the flame on the stove turned green," Angelaw1215 wrote.
Bryony Richards, a senior petrologist at the University of Utah, provided insight to Newsweek about this puzzling phenomenon.
According to Richards, the mortar appears to be made from basalt, a common volcanic rock composed of minerals such as plagioclase feldspar, pyroxene, and olivine. The green flame is likely due to the chemical makeup of the basalt itself.
"Basalt typically contains trace amounts of metals, including iron and magnesium. However, the more likely cause of the green flame is the presence of trace amounts of copper naturally occurring in the volcanic rock.
"When heated, these trace elements could vaporize, causing the flame to give off a green hue," Richards explained.
Copper, in particular, is known for producing a green color when burned, even in small amounts. Richards said that it's unlikely the basalt cookware would contaminate the food, especially since basalt is commonly used in cookware without issue.
The green flame is probably a surface effect, caused by the direct contact of the mortar's base with the flame.
While the scientific explanation cleared up some confusion, commenters on the thread were left fascinated by the chemical reaction-and even more so by the unusual method of using a molcajete on the stove.
A molcajete is a traditional Mexican mortar, most commonly used for making guacamole and salsas. However, it is not usually subjected to direct heat.
"Not once have I ever seen Mexicans heat up molcajetes. I've ONLY ever seen it used for mashing stuff and that's from many, many Mexicans," commented one user, baffled by the cooking technique.
Another user remarked: "Also, are you sure that's safe lol."
Despite the unusual technique, heating a molcajete isn't entirely unheard of. According to Mexican cuisine website Piña en la Cocina, heating a molcajete is sometimes done when it is seasoned and prepared for cooking, particularly for serving dishes like sizzling fajitas.
The heated rock helps retain warmth, making it ideal for keeping food hot at the table.