The latest curious discovery found by the Curiosity rover on Mars is an intriguing little formation that has been dubbed the "Mars flower" because it resembles the petals of a flower. The tiny translucent object is most likely a mineral formation of some kind, but some who imagine more "out-of-the-box" possibilities wonder if it could be the shell of some long-dead creature.
The NASA researchers continue to stress that is is not of biological origin, although I don't know how they can state that categorically without sampling it or analyzing it. That's not scientific and is typical of a mindset that already has its mind made up. "It cannot be of biological origin, therefore it isn't." You cannot say on one hand that you don't know what it is or what it is made of, but on the other state emphatically that it is not of biological origin. In truth, they don't know.
What NASA means to say, perhaps, is that is is most likely of mineral composition -- and it probably is. I agree with that. But that cannot be stated as fact without testing and analysis.