Whenever its about taking pictures, there's always so many options that everyone can go for. We have been specialized into taking picture of all our pearls product one by one, for the simple reason that every natural pearls are different, and cannot be generalized in only Grades color or Shapes, they might have the same specification but they are all slightly different. 
Nevertheless, if customers request us to take pictures of a particular product under the sunlight we are also very happy to do so.

So, Why don't we take them under sunlight where products may look more natural?
This for sure may work some of the time or for personal use to make incredible Instagram pictures or social media.
However, we are picturing products everyday, probably more than a thousand of pictures within a week, and for professional, it is important to be consistent and effective.
When taking pictures under the Sunlight, there are few points you need to consider such as taking pictures during morning time, afternoon, sunset or if today weather changes where sunlight might be dimmer on some days or stronger on other day, is that the best option if you want to keep shooting 100 products a day?
Theses variable affect the pearl colors pictures due to its luster "Light Reflection", therefore their colors wont be as stable especially if you are taking 1000 pictures or products in a week. You cant afford to keep experimenting everyday to find the right settings for that particular product, or would you wait for the sun today to be back again? Knowing you still have 100 products to complete for your team today?

You will keep readjusting your camera settings(based on your own feeling), which is something you would preferred to avoid as your store will have no real structure or standard to work with your team, all they will do is wait for you to do everything, and it may even slow down your team.
What you need to know is that controlled environment like a lightbox, for example using flashlight, close shot from the product with flashlight higher up:

Same product on a different Background with flashlight higher up:

Same product with Flashlight 50CM Lower:

colors will show up slightly different. Green, black or even white background, the pearls surface reflection will slightly change according to the natural background, this is how small details may changed the products images.

So knowing all of that, picturing pearls under the sunlight with a good background, our products surely will look great! We may even sell more! 
Here is one when we take them under the sunlight:

Here is in a lightbox same product:
however our goal is not making our products to look great, but we want our customer to see pearls quality in details, how spotty the pearl can be, more than looking way beautiful, as the surface of the pearl is what affect their pricing considerably and customer need to know what they are paying for!!! Especially with CMWPEARLS

Color may affect the price a bit but not as much as the quality would.
You need to know that colors settings on every devices are by default sets differently, looking on a mac, on a pc, on a different monitor, or even different smartphone, the colors are different (those are experiment we went through and we are still learning everyday). So when using a simple phone to make it look good is not our aim, we want our customer to have to option to the pearl imperfections because those are natural pearls. And having a really good camera matters to us especially when a product is worth more than thousands dollars.