I do have opposition to certain beliefs however.  For example, the famed Navaratna.  I believe, yes, that there is a sensibility that holds some kind of truth in the 'nine planetary gems', however, there are differences of opinion out there by experts (=people who know more about this kind of stuff than I do), such that inherent and handed down beliefs can be thrown into question.  For example, that the gem has to be perfect, or near perfect, or 80% clear to the human eye (now we're getting far far far from perfection, aren't we).  That the gem, if 'dirty' will bring bad luck and not good (and this coming from people who lived in a society with other people they called the 'untouchables', so I immediately drop credence in this sense of 'purity' that is capable of providing good luck (to those who could afford such a gem, which is an enitrely financially or politically elite group of people) or un-pure and provide bad luck (which derives from the opposite sense of puritanical).  In fact, I am only using this example, not to point to a particular group, but a particular kind of thinking that is inherent in much of humanity; the sense of what is pure or un-pure, good and bad, clean and dirty; and the need to determine doctrine, something concrete to believe in, particularly if it gives you structure and opportunity in the eyes of the believer).

Besides the issue of purity (as defined by the believer in whatever system of belief that defines such), is the issue of substitutions for expensive gems that are unaffordable to the average man/woman.  If you search this information, you'll find different opinions as to what can substitute for what.

Now, we enter the realm of color, and properties that lay outside the realm of just crystaline structure.

I take the example of Diamond.  Diamond is PURE carbon.  Plus, there is NOTHING like diamond on this earth.  Any substitution for diamond is going to be NOTHING LIKE diamond in terms of it's crystalline structure and what it is made of.  Plain and simple.

Yet, there are suggestions by experts for substitutions for diamond, such as morganite, quartz, white topaz, etc...

What I, myself, derive from this is that both color and crystal structure and OTHER THINGS we are not aware of, play a role in crystals and rocks having auspicious properties.  I do not believe that a crystal has to be 'gem quality', for example, crude emerald is still emerald, it still has the crystalline structure of emerald in it and therefore will emanate or do whatever else emerald will do. Yes, you need pure Ruby to make a Ruby laser (and those are laboratory grown Rubies).  Yes, one can argue that indeed you're making little lasers of a mystical, undefined, sort.  But the laser is a particular thing that focuses light in a particular way that keeps it AWAY from areas that would be infiltrated by a diffuse light.  So to, my conjecture is that gemstones don't necessarily have to be 'pure' AND that a crude gemstone is not 'dirty' and going to bring harm or bad karma to you. I believe that, as an absolute thought, that way of thinking is totally ridiculous. 

For years, red Spinel was called Ruby.  Even one of the English Royal Gems is a red Spinel once thought to be ruby, at a time that there were no scientific means of determining the difference between a ruby and a spinel.

I also think that the existence of rubies is not from the blood of a demon that fell to earth, even in a figurative sense, nor is the red in bloodstone coming from drops of the blood of Christ, even in a figurative sense.  Who is to say though that the essentiality of such beliefs holds water, such that, the results of wearing such gems seems to yield results.  Perhaps these gems, which indeed may be confering properties in and of themselves, by doing such, channeled into local thinking in order to give explanation to these properties. In fact, I am a firm believer in the ability of gemstones to confer properties to and to assist in and nutrify and cleanse, among many other possibilites.  It makes sense that besides being electromagnetic ourselves and that there are non electromagnetic particles in the billions, everywhere, capable of passing through the earth, that our bodies and minds may interact with crystal formations and rocks containing certain minerals.

My own experience has shown me that Lapis Lazuli, for example, is such an extremely powerful stone, that once I put a necklace of Lapis around my neck and two days later, had to take it off because of the effects it was having in my life.  I now wear one stone of Lapis around my neck, perhaps you or someone else might do well with a lot of Lapis, whereas me and others might not. 

 more on color...later...