Americium crystal has a hexagonal type crystalization.
Nickel has a face centered cubic crystal structure.
Diamond is a natural substance with a definite crystal structure. It is a pure form of carbon that crystallizes in a cubic system, resulting in a unique and well-defined crystal lattice structure.
Natural sources for americium doesn't exist.
Americium is an artificial element, a natural source doesn't exist.
Americium is an artificial element; minutes traces of americium may exist in uranium ores.
Not known up today
The isotope Am-241 is artificial; infinitesimal quantities of natural americium may exist in uranium ores.
Americium is an artificial chemical element, man made !
There is no crystal structure.
Any natural solid with an ordered, repetitive, atomic structure.
Yes, the mineral malachite does have a crystal structure.
Beryllium's crystal structure is hexagonal.