What exactly is a gemstone?  Webster's dictionary defines it as a mineral or petrified material that when cut and polished can be used in jewelry.  Most of us are familiar with diamonds, emeralds, rubies and sapphires, of course, but there are many beautiful gemstones that are perhaps less well-known or popular.    Because different gemstones come from different naturally occuring materials, we group them by mineral family.

Usually we have a set idea of what a gem's appearance and color should be, but nature sometimes surprises us.  Diamonds come in lots of colors, though the rarest and most valuable diamonds have little, if any color.  Say the word "Sapphire", and most of us might expect to see a deep blue stone, but sapphires do occur naturally in other colors as well.  Topaz is another mineral that occurs in many colors.  Its name brings to mind a gemstone of golden-to-amber hue, but topaz does occur naturally in shades ranging from colorless to yellow, green, red and blue.  Some gemstones (Blue Topaz, for example) are often colored by irradiation or other means.  It doesn't hurt to ask if the stone you're considering purchasing has had its color enhanced.

The Mohs scale ranks hardness on a scale of 1 to 10. The higher the number,  the harder the substance is.  If you wear lots of rings and you work with your hands a lot, it's probably best to wear rubies instead of opals (and better yet if you remove your rings before you start to work!)   Diamonds are the hardest naturally occuring substance, with a rating on the Mohs Hardness scale of 10.  We've included the hardness information so you can see how durable these gemstones are.