So this has a lot of issues.
For one, you have multiple capitalization errors. Site should be capitalized when referring to Site-19, and new sentences start with capital letters.
How do they know this was found in "A large family mine"?
MTF Omega-7 is one of the few elements I would call "non-canon" at this point. Omega-7 is certainly series 1/ressurection/lolfoundation only.
Why do they think this was made by a "complex sentient being hundreds of years ago"?
Although SCP-3316 does show various differences to normal diamond.
Fragment.
It is still unknown what other elements make up SCP-3316, nor can we currently find any, as SCP-3316 seems to be indestructible by modern means
This is really awkwardly worded, and is kind of a cliche.
After approximately 24 hours, the subject shows no signs of higher brain functionality, and then, over a period of approximately 15 seconds, the subject starts "melting" until they turn into a large amount of liquid, as if they were melting.
You say approximately 24 hours, then approximately 15 seconds. That's a really large variation next to a very small variation. It makes no sense.
You also use the word "melting" twice, and use it as a fudge word. This whole section's tone is far off of what it needs to be.
The entire Addendum is nonsensical. Why wouldn't the foundation just freeze the liquid to observe these creatures? And the Foundation would certainly kill D-class personnel if it was required to study them.