A regular hexagon will tessellate.
A hexagon will tessellate a plane so a hexagonal crystal is likely to be a hexagonal prism. In that case, it will have 8 faces.
yes it will
Because regular hexagonal shapes are able to tessellate leaving no gaps or overlaps.
Yes because it will tessellate
If their interior angles are a factor of 360 degrees, they will tessellate. Otherwise, they can't.
Yes, individually and the two together.
A regular octagon will not tessellate but an irregular one can.
Yes a triangle will tessellate leaving no gaps or overlaps
Sort of. Triangle is one of the shape that may tessellate(fit tightly). But one may argue that triangle is not a square (for sure), nor a tile (yet I think it may be) to a tessellate.
All of them can be used.Any triangle or quadrilateral will tessellate. There are 15 classes of irregular convex pentagons which will tessellate. Regular hexagons and 32 classes of irregular convex hexagons will tessellate. There are also concave pentagonal and hexagonal shapes which will tessellate.