Hi Jeremy,
Most quality multivitamins are made from natural sources. As a mineral source, some multivitamins use rock for the minerals or shells depending on what components are in the multivite.
The product you mention has very low amounts of a few components. I'd sooner go with the multivitamins at life extension, www.lef.org. I usually buy all my vitamins separately, but when I travel i use the life extension mix multi-vitamins.
The product you mention is probably fine but it doesn't contain all the B vitamins so you could end up with an imbalance, and the amounts are so low, for instance 65 mcg for vitamin K, when the requirement is 2000 mcg.
The yeast is Saccharomyces, which is a budding yeast. Best, Elaine