There are many website template companies out there today. Many of the templates actually come from only one or two main suppliers, but there are hundreds of resellers.
Here's an example of a reseller:
What you'll find there is a collection of thousands of templates that you can buy for about $62. Those templates are available for anyone to purchase when they are venturing out on their own to create a website without help from a design or programming firm.
But they are only templates, in that you have PhotoShop files and HTML pages available in the template. But there is still a lot of work to create a website.
You would need to know web programming and how to use Dreamweaver, and you need to know how to use at least Photoshop CS3, and most of the time you also need to know Flash CS3.
So many people get stuck looking at the templates in the "jewelry" category. There are thousands available and I admit that I don't know them all myself. You should consider looking into another template category if you can't find exactly what you are looking for in the jewelry category.
Here's a warning though, no one provides support on the purchased templates. They are sold as is. If you're not technical enough to figure it out, well, then you are wasting $62.
So here's what you need to do for yourself. You can buy one of those templates on your own, but first you should consider what shopping cart system you are going to use, what hosting service you are going to use, what credit card processing system you need to use, what content management system (CMS) you want to learn and use... there are literally thousands of ways you can put your website together on your own. It all depends on your own level of skill. You at least need to figure out what CMS and shopping cart you are using because some of those templates will plug right into various systems without any effort. But most will require many many hours of Photoshop and Dreamweaver work.
If all this sounds daunting, it's because it *is* daunting. If you want to do it right you need to put a lot of time into it, just like you need to put time into running a real brick and mortar store. Building a website is easy if you are technically adept and have the time to do it... time being the key word... If you don't have the time to do it yourself then you need to hire someone.
Take your time and looking for someone to help you program your site. They need to be able to work with you and follow your directions. They also need to know what they are doing. Please don't hire a first timer right from college or a trade school. You will be wasting your money if the person does not have 3 or more years experience with ecommerce. Your hired programmer needs to anticipate your needs just take care of the little things without you needing to say "please cross the T's and dot the I's"
On the other hand, if you have the money to commit to your online store, you should hire an established firm. But expect to spend $10,000 in the first year. Take an honest look around, search Google for jewelry website design or programming.