This question is not as easy to answer as you think. An Ebay article written by a jewelry maker in 2007, will lead you down the wrong path. She draws her information from a clinical trial performed by Tierra Cast. Sadly, the test is predictable as Tierra Cast is competing w/GIANT Asian manufacturers. The information is not only outdated but blatantly biased.
The first misconception about Tibetan Silver is that it is .925 Sterling. While it is comprised of pure Silver, it is definitely NOT Sterling Silver. In fact, most Tibetan Silver available today only contains a small amount of genuine Silver. The remaining parts can be any base metal even tin!
In addition to Sterling, Hill Tribe, and Bali, Fairy Dust Studio uses only quality Tibetan Silver with COPPER as the base metal and is COMPLETELY lead free. Over the years I've built relationships with my trusted sellers and have even swab tested those that I questioned. PandaHall is one of those sellers. It is just not worth the risk to roll the dice. As a consumer I want to know everything I can about what I'm working with.
Prior to 2009 the majority of Tibetan Silver on the market contained some amount of lead! However, in the last two years even the most dastardly of dealers' Tibetan Silver contained no traceable amount of lead (THANK GAWD).
Tibetan Silver has many qualities that Sterling does not. It does not tarnish, and shines up nice with a silver polishing cloth. Further, it is a cheaper alternative, and wearable for those w/a Sterling allergy. I actually prefer working with it as it is more durable. Cheap imitations will easily break.
Regardless of the pro vs con opinions, be safe and informed when purchasing anything that comes in contact w/your skin, or children.