Spinels are similar to the garnets and diamonds that you know of. They’re a little bit refractive, and they also have the same crystal directions and physical characteristics. 

They also come with a cubic crystal type of system, and they’re characterized by the octahedron and sort of crystal shape, which looks like different pyramids back to back. There are a lot of spinel crystals that are quite common within nature. 

They also create crystals that are flattened, and they look very different from the octahedral types of crystals.  This shape that’s flattened and created happens when you have pyramids that form within each of these, and they rotate against everyone for them during the growth period. 

They’re known by many scientists as twinned crystals. 

Some larger cuts of these gems are made from good, twinned types of crystals, and usually tend to be shallower, and are judged based on the beauty that occurs overall, rather than just on the proportions of these by themselves. 

They are like garnets; in that they are part of the same mineral group and share the same structure of crystals.  However, not every one of them creates a transparent crystal that’s suitable for the use within jewelry. But there are a variety of hues, including red that’s like a stoplight, orange, pink that’s vibrant, different purple shades, and even blue and purple that comes with this.

Some of the more intense types of reds are due to chromium, and the same is said about pinks. The more chromium, the greater the reddish hue.  The purple and orange does come from chromium and iron mixed together. 

Blue and violet types of spinels are attributed to the trace iron, and other vibrant colors. The cobalt is what makes them look more bluish.