I obviously have an obsession with jewelry. As such, I do try to buy really good jewelry books when I have the money. These types of books are normally very expensive, but the quality is so amazing, they far surpass any images found on the internet. I have looked through dozens of jewelry books, either at libraries or bookstores, and I am quite proud of the small, but high-quality collection that I own.
These are the favorite jewelry books that I own:
The Queen's Diamonds, by Hugh Roberts. Has a list price of $95 but I got it for the discounted price of $67.49, available at Amazon. I just recently purchased this, and let me tell you, it has huge, amazing high resolution images of most of Queen Elizabeth II's important jewels, as well as their respective original owners wearing the jewels. The book is separated into sections from the jewels that Queen Victoria added to the collection, all the way through Elizabeth II.
Jewelry: Ancient to Modern, by Walters Art Gallery. I found this book at a yardsale for $2. Its one great downside is that because it is from 1979, when color printing was expensive, most of the images are grasyscale. There is a large selection of jewels from the past 2000 or so years. It has been a great inspiration for me when making my own jewels.
Tiara, by Diana Scarisbrick. This book contains many full-color images of tiaras, but the downside is that some of them are very small or not high resolution. The designer also did this strange thing where all the tiaras are cut out of whatever background they were originally on. It is incredibly obvious, and not very well done. Having said all that, if you find this book for a good price (I would say less than $30), it does contain a treasure trove of images. I bought this new for about $35.
Jewelry, by HART Picture Archives. The best part about this book is that all the illustrations are public domain, meaning you can make art out of these and actually sell it without any fear of copyright infringement. These types of books were really popular in the days before computers and software(mostly Adobe Photoshop) took over. There is only a tiny section on tiaras, but the other images are just as lovely. I paid about $5 for this at a secondhand book shop.