Some things that stand out to me:
1. You really need to beef up your containment procedures. Don't just say "it's here". Explain in as much detail as possible how it's being contained. Where exactly is it contained? What is it contained in or on? How are these procedures to be enforced? Act like this is a real object that needs real security.
2. You say "interaction is to be recorded", but that's too vague. How is it to be monitored? Who is allowed to test it? When is it to be tested and is there a testing schedule?
3. There are a lot of grammar and spelling errors that need to be ironed out and it's making the article a nightmare to read. If you're not a native English speaker, I'd suggest asking someone who is to sort it all out (I am and would be more than willing to do so).
4. Nothing that can be accurately weighed has an approximate weight. Be specific: I don't know if it's 750kg or 752kg and I might need to. Length and depth might be useful measurements for this object too. If you're unsure, look up how big a 750kg slab of argentine would be.
5. It actively changes over the course of days, but how many days? Again, specifics. If it fluctuates, say so using specific numbers (e.g. "Testing has shown that changes can take between 3 days and 2 weeks).
6. This SCP has promise, but it suffers from being too vague. It seems to "just change", but why? And how do people automatically know it's a code without intense study. That's why I can see something in it, because code based articles like SCP-1050 can be a lot of fun and create a lot of discussion if the reader is allowed to know everything the researchers do. I'd suggest coming up with what the object actually means and having almost a detective mystery and maybe end with the article being unsolved.
An SCP similar to this (although without the code subplot) that I love is SCP-800- its knowledge of when, why and how to change is what makes it so amazing. Keep it up and this could be pretty cool.