My first critique.
I like the concept; it reminds me of the Lost Ark. I also like the photo you selected.
That being said, my biggest concern is the labeling of Thaumiel. Just what makes this scip a Thaumiel class? What makes it so hard to contain? I understand it blows up whatever building it gets brought into, but if it's capable of doing that how was it brought into a facility and used to stop a containment breach?
Wouldn't it be more effective for the foundation to buy off the land in which the anomaly was located, create a cover story, set up some security patrols, and maybe even make a remote testing facility nearby?
In addition, how can 45% of people wishing to convert to Christianity be successful? What is the measure of success?
I feel like this SCP has a good premise, but could use a lot of revision to make it make sense, as well as some format adjustments.
I wish you luck and I really hope this was constructive. :)
EDIT- If the Box were capable of blocking light, it would be invisible, I think.