I feel like this was rushed, as there are typos in the article, even the first paragraph, such as:
D-Class personnel where neutralised by SCP-XXXX after failure of several safety protocols.
The entry seems overly specific in areas that don't contribute to the article. The exact numbers of 2.14 m and 544.31 kg for the entity stand in stark contrast to the "no official measurements have been taken". The rare earth seems to be there for a mysterious purpose, but I don't feel it adds to the article.
You also use speculation in an odd manner.
It is said to weigh somewhere around 50 kilograms
SCP-XXXX-1 is speculated to have a physical hardness of around 5000 Mohs
This alludes to the creator ( [REDACTED] ) initially striving for a more realistic structure.
Subjects seem to be completely conscious during these actions
It is as of yet unclear what the intentions of the creator where when creating this sculpture, and whether or not the creator was aware of the anomalous behavior of SCP-XXXX, or if it was later created by another source.
SCP-XXXX will stand up to embrace the subject, supposedly in a sign of gratitude.
These are statements that don't really fit in with scientific tone. Scientists don't usually put their speculation in the middle of an article (in real life, some have a 'potential further avenues of research' section, but only at the end). These documents serve a life-and-death purpose, protecting employees. What they know should be written down with confidence, and the unknown should be omitted or, if absolutely necessary, not be written with speculation as to truth.
Brain wave analysis is thrown in casually, as if it's common for the foundation to be able to transcribe thoughts. This is a major leap forward compared to other articles, and shouldn't just be thrown in as an easy way to get around how you recorded the conversations.
The article has several plot holes:
SCP-XXXX was wrongly identified as a potentially dangerous reality bender and trapped inside SCP-XXXX-1 at some point in time by the Foundation.
Then why doesn't the foundation not even know how much it weighs? If this is the redaction power, that should be mentioned.
SCP-XXXX has proven itself a reliable and honest person, and its account of its unjust containment at our hands is to be trusted.
Then why is it in containment? This is completely unprofessional. If it's a format screw, showing that it's convincing the person writing the article that it should be freed, then this needs some more buildup.
The conversation follows a common pattern with beginning writers (which I've done as well): call and response. In this pattern, each person repeats or answers what the last person says, and then says something, which the other person repeats, etc. like so:
A: Are you hungry?
B: Am I hungry? Yes. Are you happy?
C: I am happy. What are you doing?
D: Doing? Just stuff. And you?
E: Me, I'm doing stuff too.
See how it lacks action and excitement? Real conversations include changes of topic, interjections, twists and turns. Try reading your conversation out loud.
Similarly, the note to Dr. Lang sounds mechanical, a recitation of events, whereas most notes are included to show an element of humanity.
Finally, the hash thing looks cool. I didn't guess the password, though.