- Odd Containment Procedures: I literally laughed when you had two guards posted to prevent the SCP from getting stolen. First, guarding the object to prevent unauthorized access or theft is typically not necessary to put into the Procedures, it's assumed to be covered in the unwritten "Standard Containment Procedures". Second, it literally weighs a ton, and is 15 feet to a side. How is anyone going to steal it without a work crew to bust down walls between it and outside of the building? Considering what is required to steal the SCP in the first place, almost all armed personnel on site will converge on whoever is making the attempt.
- Bad Redactions: Allright, you redact the name of an acid, and then proceed to describe the comparitive strength of said acid. By doing so, you have completely negated the point of redacting information (which is to hide information that one does not have access to see). In this case, you're describing a Superacid, and there's only one that's within that range- Fluoroantimonic acid, which is either 1016 or 1019 times as strong as Sulfiric Acid, depending on the source.
- Generic Magic Item: Simply put, your SCP exists without a story or context, relying on its core anomaly to succeed. In this case, the core anomaly is boring, and thus unlikely to succeed without major changes.
The major issue here is that your SCP lacks any context or story. It simply exists without rhyme or reason. It's a block of glass that is, for all intents and purposes, indestructible. And you go nowhere with it. Your testing log doesn't do much beyond simply stating what you already put in the description (which is generally a bad thing in terms of SCPs).
I can think up of several ways that it might be more interesting, specifically an experimental procedure to make literal bulletproof glass by Prometheus Labs comes to mind, but even then there's only so much that can be done with this idea. IMO, the idea and concept needs major reworking before it can be made into a viable SCP, just due to the sheer slope of difficulty in making it interesting as-is.
In this case, I'd suggest you lurk more and put this SCP on the back burner. Read more articles, especially in Series II and III. Look around the brainstorming and draft sections to see what others are coming up with, and maybe take a peek in chat and rub elbows with other members, tossing ideas around. Then, come back.
And remember, most modern SCPs aren't just reports on objects, but stories in the form of reports on objects. When you're reading through SCPs, don't look at just what the object is, but take a look at what happens over the course of the article. What does the SCP say or imply about the Foundationverse? How did people react to it? If it was artificially made, who made it and why?
Now, as for your tale…
Don't. Scrap it and try something else. As it stands, it's basically a derivative of SCP - Containment Breach, and trying to make it work is simply unlikely to succeed. Unless you write it extremely well you'll likely be seen as ripping off of the game. This is on top of possible headcanon violations regarding how the game handled how the Foundation would distribute SCPs (long story short, don't keep things that will cause havoc if let loose at sites with mutliple SCPs).
Trying to make it work will likely just be an exercise in frustration, tears, and failure.