Which gemstone should I wear according to my kundli?
The answer the Parashari school gives is a lordship answer. Three houses are counted from your lagna (the rising sign), and the grahas that own those three signs supply the three stones the tradition names. The lagna lord gives the life stone, the 9th lord the lucky or fortune stone, and the 5th lord the benefic stone. Where one graha owns two of the three signs, one gem covers both roles, which is why many charts return two stones rather than three. Nothing in this depends on a birth month, a Sun sign or a name. It depends on the sign rising at the moment of birth, which changes about every two hours, so an approximate birth time can move every one of the three lords by a whole house.
The life stone: jeevan ratna, from the lagna lord
The lagna lord is read as carrying the body, the constitution and the direction of the whole chart, so its gem is the one classical writers describe as worn longest and changed least. Because the lagna lord is by definition the 1st lord, and the 1st is both a kendra and a trikona, this stone is almost never held back by the dusthana rule. The question about it is nearly always strength rather than lordship.
The lucky stone: bhagya ratna, from the 9th lord
The 9th is bhagya bhava, read in classical writing for fortune, for the father and for the guru, and its lord supplies what popular practice calls the lucky stone. It is the one most often asked for by name and the one most often sold without a chart being read at all. The calculator prints which sign is your 9th, which graha owns it, where that graha stands and whether the rule set actually selects its gem.
The benefic stone: karak ratna, from the 5th lord
The 5th is purva punya bhava, read for intelligence, for children and for the fruit of earlier merit. Its lord gives the third stone, and the tradition treats it as the supporting one of the three rather than the leading one. Where the 5th lord also owns a dusthana and no kendra or trikona beside it, the same withholding rule applies here as anywhere else, and the report says so rather than quietly dropping it.
What are the nine gems, and what is each called in Hindi?
One ratna per graha, and each has a Hindi name it is known by across India. The Sun takes ruby (माणिक्य, manik), the Moon pearl (मोती, moti), Mars red coral (मूंगा, moonga), Mercury emerald (पन्ना, panna), Jupiter yellow sapphire (पुखराज, pukhraj), Venus diamond (हीरा, heera), Saturn blue sapphire (नीलम, neelam), Rahu hessonite (गोमेद, gomed) and Ketu cat's eye (लहसुनिया, lehsunia). Beside each, the tradition accepts an upratna: a substitute stone read as carrying the same graha, such as red spinel for ruby or moonstone for pearl. The report above prints the upratna list for every stone it names, because the substitute is part of the tradition rather than a compromise invented later.
Why does the tradition refuse a gem to some grahas?
Because of a single sentence the whole rule set turns on: a gem strengthens its graha, it does not pacify it. Classical writing treats a ratna as amplifying whatever its graha already does in that particular chart, which means the stone of a graha the chart reads badly is the last thing the tradition would hand over. This is the exact opposite of the way gems are usually sold, where a difficult Saturn is met with a blue sapphire and a difficult Rahu with a hessonite. The rule set here follows the texts instead: a gem is selected for a functional benefic that is measurably weak, and withheld from a functional malefic however weak it measures. We list what it withholds and why, not as a prescription of our own but as what the tradition itself states.
The dusthana lordship rule, and its own exception
A graha that owns only the 6th, 8th or 12th from your lagna, with no kendra or trikona lordship beside it, is the standard case for withholding its gem. The exception matters as much as the rule: where the same graha owns a dusthana and a kendra or a trikona together, the tradition lets the kendra or trikona lordship decide and the gem returns to the table. The report prints every house each lord owns, so the working is visible.
Neelam, gomed and lehsunia carry an extra warning
Almost every published treatment adds a caution to the Saturn, Rahu and Ketu stones and asks for a trial period before one is set permanently. We repeat that caution because it is part of the tradition being reported, not because a stone has been shown to do anything that would need one. The two nodes own no sign at all, so they have no lordship to strengthen, which is the structural reason their stones sit outside the three-lord rule entirely.
How does the calculator decide a graha is weak?
By Shadbala, the six-fold strength measure of classical Jyotish, and against each graha's own published requirement rather than against a common threshold. Shadbala adds sthana bala, kaala bala, dig bala, cheshta bala, naisargika bala and drik bala, expresses the total in rupas, and sets a different minimum for each of the seven grahas: the Sun needs 5, Mercury 7, Jupiter 6.5, and so on. A graha below its own minimum is what the rule set reads as weak, and a weak functional benefic is precisely the case in which the texts prescribe its stone. The figures on this page come from the same computation that drives our Shadbala calculator, so the two pages cannot disagree. Rahu and Ketu carry no Shadbala figure at all, which the report states rather than inventing one.
Rupas, virupas and the per-graha requirement
Strength is counted in virupas and printed in rupas, sixty virupas to the rupa. The part people miss is that the requirement is not shared: Mercury is asked for seven rupas and the Sun for five, so a graha at six rupas is strong in one role and weak in another. Comparing raw totals between grahas is therefore the wrong reading, and the ratio of the total to the requirement is the number that carries meaning.
Whole-sign houses, and where a cusp system differs
Houses here are counted whole-sign from the rising sign, which is the convention this site uses throughout and the one classical Parashari practice assumes. A cusp-based system (Bhava Chalit, or Placidus in Western practice) can put a graha near a boundary into the adjoining house, and where that happens the 9th or the 5th lord being read can change with it. The report names the sign of each house so the difference is visible rather than hidden.
Which finger, which metal, and on which day?
The tradition sets each of the three separately, and the report prints all three for every stone it names. Ruby goes in gold or copper on the ring finger and is first worn on a Sunday; pearl in silver on the little finger on a Monday; red coral in gold or copper on the ring finger on a Tuesday; emerald in gold or silver on the little finger on a Wednesday; yellow sapphire in gold on the index finger on a Thursday; diamond in silver or platinum on the middle finger on a Friday; blue sapphire in iron, steel or silver on the middle finger on a Saturday. Each graha also has a mantra the texts give with its stone, printed in Devanagari beside the setting. These are the tradition's conventions, reported as such.
Why the metal is specified at all
Classical writing pairs each graha with a metal as firmly as it pairs it with a stone: gold with the Sun and Jupiter, silver with the Moon and Venus, copper with Mars, iron with Saturn. The setting is treated as part of the prescription rather than as jewellery, which is why a traditional recommendation names it. Where two metals are given for one stone, the texts read them as alternatives rather than as a ranking.
The weekday, and the graha's own hora
The day named for first wearing is the weekday the graha rules: Sunday for the Sun, Monday for the Moon, and so on round the seven. Some lineages narrow it further to that graha's own hora within the day, or to the shukla paksha. This is timing convention in the tradition, of the same kind our muhurat pages set out for other undertakings, and it is reported here rather than prescribed.
Is a lucky stone by date of birth the same thing?
No, and the difference is worth being clear about because the two are sold under the same words. A "lucky stone by date of birth" table usually means one of two things: a birthstone list, which is a twentieth-century jewellery convention rather than a Jyotish one, or a stone read off the Sun sign. Neither is what the Parashari rule set does. This page counts the 9th house from your lagna, finds the graha that owns that sign, and tests it, a chain that needs your date, your time and your place, and that gives a different answer from a table keyed to a month alone. It is also worth saying that rashi means the Moon's sign and never the Sun's, so even a genuinely Jyotish table keyed to rashi is answering a different question from this one.
Does wearing a gemstone actually change anything?
No measured effect of wearing a gemstone on any outcome has been demonstrated, and this page does not claim one. What the calculator prints is what a specific classical rule set selects from a specific chart, with the working shown, so that a reader can see the reasoning rather than being handed a stone and a bill. That distinction matters more here than almost anywhere else on this site, because gemstones are expensive, the trade around them is not uniformly honest, and a recommendation is a common way of turning worry into a sale. The tradition's own advice is the one we would repeat: have a jyotishi read the whole chart, unhurried, before spending money on any stone.
How this is calculated
Nirayana rashis with the Lahiri (Chitrapaksha) ayanamsha and whole-sign bhavas, computed to arc-second accuracy. Sunrise and sunset are the ones almanacs show, the Sun's upper edge with refraction, so the daily windows agree with the calendars you compare them with. More on our method.