Will be going to Delhi, Jaipur and Calcutta in late December - early January. Any recommendations on where to buy stones and jewelry? Am looking for reasonable prices and good quality. Any other cities in Rajasthan apart from Jaipur that are good for jewels?

Thanks!

I think the place to buy jewelry in India is where you see something you love (unless you're shopping for resale). There's a street in Old Delhi, Dariba Kalan Rd, with a number of stores. Your accommodation can point you in the right direction. I bought nice earrings there.

in Jaipur, the gem palace is worth a visit.. not for bargains, but for the experience

Silver is a buy there. Both old tribal and new modern pieces. I think it was Jodhpur where I bought a lot of tribal stuff. Age questionable, but looks good and reasonable. The town at the base of Nemrana fort has 2 silversmiths that do newer designs. I always get compliments on my Indian jewlery, especially for its uniqueness.

If we talk about traditional jewellery than you should go for Jodhpur.

Go to a reputable shop to buy these items. Jewellery is a cottage industry in Jaipur. There are a lot of smart Alecs who would want to dupe you! The modern technology helps them in their enterprise. You must have basic knowledge to segregate the genuine from a fake or treated stuff.
The Bohra's at Jewels Emporium (MI Road), are fine jewellers. Am yet to hear anything negative on them and would, till I hear that, trust them. The Tholia's are a good option, clean businessmen. The Gems Palace is a by-word in Indian jewellery. I have personally met, and paid respects, to the late Maharani Gayatri Devi of Jaipur at their MI road showroom.
For Silver Jewellery it is Amrapali.
All these shops will have antique artifacts, which are not on display, but all the same on their inventory. These artifacts have come from old feudatory households which may have fallen on bad times or may have been sold to meet a pressing need. These are some of the finest articles, I have ever seen.Ethics demand that these are not openly displayed, in case these are recognized!
In India, we do not walk into any or every shop. Each family has their own jeweller. Generation after generation one goes to a particular 'saraf' (Jeweller). The family bond precludes a mishap.
Jaipur is the place to shop and a delight, so long as you are careful!

The city of Jaipur is famous for its markets in Jewellery and semi precious stones. Shoppers can also get costume Jewellery made as per their own designs. The price in such cases is quoted usually per gram weight of the material, plus per gram added for the labor in making the Jewelery. The main shopping markets in Jaipur are Jauhari Bazaar, Nehru Bazaar., Bapu Bazaar, Chaura Rasta, Mirza Ismail Road and Tripolia Bazaar

A good rule of thumb when buying jewelry in India is don't pay a lot of money thinking you're getting genuine gold, diamonds, rubies, etc. Buy something because you love the design and won't be crushed to learn the jewelry is costume/fake when you get back home.

In Delhi, you can go to Delhi Hatt Market to buy gemstones and silver jewelery. And when it comes to Calcutta, try Anjali jewelers, Sawansukha and Chique jewelry store.

I visited a fabulous jewelry store in Delhi while searching for gold bangles for my grandma. Everything is sold by weight, with a small fee for craftsmanship. I will try to find the name and report back.

One thing to remember- in India, most gold is 22K so quite different in color from the typical 10/14K that is popular in the west. Even quite different that 18k.