Call of the Arcane blood: ReCo30 (Mu): Base 10 (5 paces, up 5 for 50 paces), +2 voice, +1 Mu req, +1 Part.
The caster summons a small portion of the targets blood to his palm or pocket in the form of a red gem.
Generally, holding/handling/storing a gem is far easier than transporting or handling liquid blood but I've realised there might be a problem. Won't the blood simply return to it's original form immediately, making the muto part of the spell entirely redundant?
You'd need to summon it into something as One Shot pointed out, and in that case why would you bother with the muto component. Or, you can give the spell a longer duration than momentary. Or (most complex option) do something tricky with an enchanted device/ rego vim spell/ familiar/ magus buddy that allows you to get a second spell cast at the same time.
apart from One Shot's remarks, which I agree with, if you wanted to go with your original spell, you might also need a Terram casting requisite to get the form of a gem - this wouldn't increase the level, in my opinion, but might affect your casting total.
If you would need the Terram requisite or not, is totally up to your troupe.
Based on the Core book, my guideline is: 'Would the magic still work in a different way? Do you benefit significantly because the added effect in question?' If yes, you need the requisite.
Example MuCo Cat's Eye, this spell wouldn't work, alas the animal requisite is free.
In your spell: could you gather the blood without transforming it to a gem?
Yes, it would. Transforming the blood to a gem is definitely a significant bonus (transportation, purity, etc).
I might be considered a more strict GM, as additional to the Mu (+1), Te (+1) requisites I would add another (+2) magnitudes for transforming it to a 'gem' based on the MuTe guidelines. -> Re(Mu)Co(Te) 45: Base 10 (5 paces, up 5 for 50 paces), +2 voice, +1 Part, +1 Mu req, +1 Te req, +2 effecting gem.
I know this might be not the answer you are looking for.
Generally speaking when the requisite is part of the effect (transforming X to Y needs Y to be requisite of X...) it's free. That's why MuCo(An) in Eyes of the cat is a free requisite.
In your effect, the transformation is an additional (and valuable, not only cosmetic) effect : a gem doesn't fall on the ground and then isn't spoiled like blood. A gem is solid. And, by the way, since it has a muto , and muto cannot be permanent because it changes unnaturally the blood, it needs a duration.
By the way, I think your base is incorrect because the MuCo(Te) to turn in stone is a higher level than 10. Serf's parma, so I think 20 is the base. Thus your spell is Re(Mu)Co 45 (base 20 (muto higher than rego), +2 voice, +1 muto, +1 diam, +1 part). Oh I just thought about it, turning to gem IIRC is +2 magnitude, thus level 55 and mandatory ritual by level.
I would use an item with inherent container (a bottle with a rego effect for example) because the item:
allow level higher than 50 if the level is the only reason the effect would be ritual
doesn't need to turn the blood in gem, lowering base to 10, erasing the need for requisite and higher magnitude do to gem material.