The Seven Planetary Metals and Their Weekdays

A double seven

The whole thing rests on a coincidence that ancient eyes did not read as one. In the sky, visible to the naked eye, exactly seven bodies moved against the fixed stars: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn. And in the workshops, well into the Middle Ages, exactly seven metals were known in pure form: gold, silver, copper, iron, tin, lead, mercury.

Two sevens, one above and one below. To a way of thinking that treated correspondence as a basic law of the world, linking them was not an invention but a discovery. The assignment is attested in Greek alchemical texts of late antiquity, and by the Latin Middle Ages it is so taken for granted that scribes use the same sign for the planet and for the metal. Open a manuscript, find the sign for Saturn, and you have to work out from context whether the writer means the planet or the lead.

The seven assignments

Planet	Metal	The logic behind it	Day
Sun	Gold	does not tarnish, keeps its shine — the imperishable	Sunday
Moon	Silver	white shine, darkens and brightens again — like lunar phases	Monday
Mars	Iron	weapons and tools, rust-red like the planet	Tuesday
Mercury	Quicksilver	liquid, volatile, impossible to hold — the fastest planet	Wednesday
Jupiter	Tin	bright, soft, ringing; the large benign planet	Thursday
Venus	Copper	warm red tone, mirrors of copper; Cyprus gave the metal its name	Friday
Saturn	Lead	heavy, dull, sluggish — the slowest visible planet	Saturday

What stands out is that none of this is arbitrary. The assignments follow a double observation: how the planet behaves in the sky, and how the metal behaves in the hand. Saturn is the slowest naked-eye planet; lead is the heaviest and most sluggish of the seven. Mercury is the fastest; quicksilver is the only liquid one. That is not mysticism. It is a classification system doing the best it can with the instruments of its time — which is to say, with the eye.

The orbital periods make the point better than any argument. The Moon takes about 27 days, and gets silver. Mercury about 88 days, and gets the metal that will not sit still. Venus about 225 days, copper. The Sun a year, gold. Mars about 2 years, iron. Jupiter about 12 years, tin. Saturn about 29 years — and gets the heaviest thing on the bench. Line the two lists up and the ranking is the same ranking.

Why the week has seven days

The planetary week is the longest-lived descendant of this system, and English speakers carry an unusually legible version of it.

The Romance languages say it outright: lunedì is Moon-day, martedì Mars-day, venerdì Venus-day. English overwrote the middle of the week with Germanic gods of matching function rather than deleting it. Tuesday is Tiw's day, the Germanic Mars. Wednesday is Woden's day, standing in for Mercury — which is why French still says mercredi and English does not. Thursday is Thor's day, the thunder god who took Jupiter's place. Friday is Frigg's day, for Venus.

And then there is Saturday, which never got overwritten at all. It is simply Saturn's day, the one weekday in English that still names a Roman planet to your face. German lost that one and kept the others differently — Samstag came in by way of the Sabbath. Sunday and Monday need no explanation in either language.

So anyone working with planetary days is not using a modern invention. They are reading the calendar the way it was built. If you want the day-by-day version with something to actually burn, the companion piece on planetary incense by weekday covers the timing side in practice; this article is the metals.

From lead to gold — what that actually meant

The seven metals were never a flat list. They were a ranking: at the bottom lead, which tarnishes, is soft and alloys with anything; at the top gold, which stays what it is. The other five sat in between, in orders that varied by source.

The famous transformation of lead into gold means two things at once inside that ranking — an attempt in the flask, and an image of a maturation path with transformation at the end. Whether a given alchemist was pursuing one, the other, or both was often less clearly separated in his own mind than we would like it to be today. What the work looked like from the inside is the subject of the piece on the gold-makers, where the stakes were considerably higher than a metaphor; the interpretive tradition is covered in spiritual alchemy.

Two of them are poison

Here the poetry stops. Two of the seven classical metals are seriously hazardous, and both were handled casually for centuries.

• Lead accumulates in the body and damages the nervous system, blood formation and kidneys. Children are at markedly higher risk, and there is no known safe blood lead level in children. Old lead-glazed dishes, leaded solder and historic paint pigments do not belong in household use. In the US, lead paint in housing built before 1978 remains the most common domestic exposure route.
• Mercury evaporates at room temperature, and the vapor is the actual problem — it is odorless and it is inhaled. A broken antique thermometer is a case for ventilation and care, not curiosity; it should never be vacuumed, which disperses it. The EPA publishes cleanup guidance for exactly this situation.

None of this means you cannot work with Saturn or Mercury. It means you work with the timing and the sign, not with the substance. That distinction matters more than it sounds: the historical practice of handling these metals directly is precisely the part that does not survive contact with what we now know.

What we don't promise

• That wearing a metal on its day influences outside events. There is no evidence for it.
• That metal applications or metal-containing preparations do anything for health.
• That there is only one correct order of the seven. The sources rank them differently.
• That lead and mercury are harmless if you are careful. They are not.

What remains is a classification system that grew out of observation, survived two thousand years, and is still in your calendar every Monday.

Practically: how to work with this

• Start with the weekday. You do not need any metal to use the system. The day is the metal — put the Mars-shaped task on a Tuesday and notice what that does to how you approach it.
• Work with what you already own. A copper wire, a pewter cup from a flea market, a silver ring from family. The point is assignment, not purity.
• Hands off lead and mercury. Both are toxic. If you want Saturn or Mercury in the scheme, use the sign, the day or a color — never the substance.
• Learn the seven signs. Half an hour of work. Afterwards you read old engravings and manuscripts differently, and you start noticing how often they turn up in modern design.
• Connect it to what you already do. If you work with candle colors, you own half the system already; the correspondences overlap heavily.
• Set an end. Twenty minutes with a fixed beginning is worth more than a whole evening of good intentions.
• One week, seven metals. Each morning, note which planet carries the day. Each evening, find one single place you saw its metal — copper on a pipe, iron on a railing, tin on a lid. Nothing more. After seven days you will not have memorized the assignment, you will have found it, and that holds differently.

Frequently asked questions

What are the seven planetary metals?
Gold for the Sun, silver for the Moon, quicksilver for Mercury, copper for Venus, iron for Mars, tin for Jupiter and lead for Saturn.

Why exactly seven?
Because two sets of seven met. Exactly seven moving bodies were visible to the naked eye, and until the Middle Ages exactly seven metals were known in pure form.

Why does lead belong to Saturn?
Because both behave the same way. Saturn is the slowest naked-eye planet, taking roughly 29 years for one orbit. Lead is the heaviest and most sluggish of the seven — dull, soft, slow.

What do the weekdays have to do with it?
The seven-day week assigns each day one of the seven planets. In English several days were overwritten with Germanic god names — Tuesday for Mars, Wednesday for Mercury, Thursday for Jupiter, Friday for Venus — while Saturday still openly names Saturn.

Are planetary metals dangerous?
Two of them, yes. Lead accumulates in the body and damages the nervous system, blood formation and kidneys. Mercury evaporates at room temperature and the odorless vapor is inhaled. Work with both through sign and timing, never through the substance.

Is the assignment a modern idea?
No. It is already attested in Greek alchemical texts of late antiquity, and by the Latin Middle Ages it is fixed enough that the same sign serves for planet and metal.

Sources & further reading

• History-of-metallurgy literature on the seven metals of antiquity and how they were won and worked.
• Greek alchemical texts of late antiquity and medieval sign tables for planets and metals.
• Historical-linguistic accounts of the planetary week and its Germanic overwriting in the English weekday names.
• Standard toxicology on lead and mercury; US CDC guidance on childhood lead exposure and EPA guidance on mercury spill cleanup.
• Orbital periods from standard astronomical reference data.
• Further reading here: planetary incense by weekday · spiritual alchemy · the gold-makers.

This piece places a historical correspondence system in context. It contains no claim of efficacy and no health claim. Lead and mercury are toxic and do not belong in household use. Questions about an order: 28@templeofdesire.com.