The precious stone known as the diamond can be any shape, depending on how it has been worked. It will be faceted (that is, it will have a number of smooth flat surfaces, separated by angles, which reflect the light and make it sparkle).
The shape known as the diamond is a plane of four equal sides. Two of its opposite angles are less than 90 degrees (for example, 70 degrees) and equal to one another, and the other two opposite angles are more than 90 degrees (for example, 110 degrees) and equal to one another.
A raw stone of any gem can come in all the shapes and sizes of stones. A raw stone's value is only finalized once it has been cut and polished to show off its best qualities.
To review some of the different cuts for gemstones, follow the link, below.
a diamond's crystal structure has a cubic arrangement of atoms. However, diamonds can be cut to any desired shape.
Most natural diamonds are roughly in the shape of a octahedron. For jewelry, diamonds are cut in a variety of shapes.
The shape is a four-sides shape, it is a polygon
The geometry term would be a rhombus.
Square
rhombus
A rhombus is just another name for a diamond. So therefore, a diamond shape.
I believe it is Rhombus
rhomboid; rhombus
you have two diamonds and a cross
a quadrilateral sideways, a pentagon looks like a crown.
a rhombus
Argyle
a rhombus
A diamond shape is also called a "lozenge".
Diamond is the hardest known substance, but one diamond can scratch another diamond. If that was not the case, there would be no way for jewelers to shape diamonds as they do, into faceted jewels, instead of lumpy stones.