Sorry I feel like I didn't get to the topic of mana enough. So let me explain!!
Mana is the smallest form of matter—smaller than a quark. There is only so much mana in the world. When the earth was rested mana was born and given an identity/purpose. Basically mana already has an identity and form, and is only alterable within that existing structure. Though, mana is everything and can be anything at the same time. It is possible to change mana by will because i said so.
—Mana paths aren't random!!! This is a very important detail that I fear I may have skipped over. Mana appears as chemical compounds. For example CO2 (carbon dioxide). The mana appears to have two Oxygen molecules and one carbon molecule. The molecule can be seen at a deeper level but for Agnes she only sees the chemical for now. The mana flow(what agnes sees) is just these compounds. If she looks at a rock she can see the chemical. It's not tightly held together though, it's spread out inside the object—yet it's still visible.
A molecule can be changed and discarded. This is the manas identity, and its purpose is to act as carbon dioxide. Agnes can understand mana well because she is familiar with it. As a scientist she has mastered the periodic table and what they create. If you use CO2 as an example, she can change the Carbon into hydrogen and then change one of the oxygen molecules into hydrogen to create water. Though she could remove the two oxygen molecules(releasing them into the atmosphere) and change the compound into just carbon.
When it comes to Agnes's abilities she can alter the manas identity by will. Though it isn't unlimited! As stated before there is only so much mana in the world, and the created mana already possesses a form. The rules are as follows. Mana has a value. Of which can be determined by the concentration of mana in the certain object (singular particles can be gathered together). I would like to specify what mana value is, if you don't understand what i'm implying let me clarify. Mana value is basic Chemistry. You just count the amount of chemicals in the compound to determine the mana value(basically a equation,) if you still don't understand it's fine—Agnes has to do the math anyway(me💔💔). If you take a rock for example(shown in the last chapter) you can remove the other chemicals to create a new composition though you CANNOT create new mana out of thin air, for now! I would like to add that it is possible to have multiple compounds in one object(multiple compounds in one)—of course its not found naturally, by artificially reinforcing the object it can gain traits/be more durable and strong.
And sorry i'm not like a nerd or anything i just find science and yuri to be amazing and couldn't help but combine them😓