Hi Lorenzo -
There is a saying in English that applies to me:
"I have no horse in this race". So, I feel that I am unbiased in my opinion and can say what I feel. IMHO, the version that you posted in #8 looks like a flat, uninteresting, 2D shape that doesn't particularly remind me of a diamond. It feels more like we are looking down at a Manta ray swimming in some blue water (interior lines not withstanding). It would not attract me to this business. In contrast, I feel that the version of the shape that Sam posted is vastly better: elegant, simple, catchy, just the right amount of suggestion of three dimensionality, sophisticated, etc. His design is right along the lines of what was suggested by every other person who responded to this thread: Chris, Clare, and dv8.
With respect to your statement in post #8 that
"you don't want a real diamond", in the real world of commercial design, it just doesn't matter what *you* want. In this business, one must have humility in the sense of realizing that there is a very good chance that what pleases you personally may not be the way a majority of other people will see your design. All that really matters is producing an *effective* design. In other words, something that catches the eye of many viewers and brings them into the "store" (either real or virtual). This is why important commercial designs are always evaluated by
focus groups,various kinds of
blind testing, and a myriad of other techniques. To give you an idea of how supremely important unbiased advice is in design for marketing, just click on few of the links in this
glossary of marketing terms. Follow through some of them to articles such as this on on
"concept testing".
Whether you realize it or not, in this thread, you have been given advice by people who collectively probably have more than 150 years of experience with Photoshop, and at least two of which have been paid by others to make good designs for their entire careers (ie, as designers). In contrast, by your own admission, you are just starting out and have only two years of experience with PS. You should listen to what they say. Their goal is not to be contrary or to be show-offs, they are just trying to be helpful to you.
I hope you take this friendly advice from me about listening carefully to what others recommend as another attempt to be helpful.
Tom