Quartz

            Quartz is one of the most common minerals in the earth’s crust.  It occurs in granite bedrock and sand on the beach, it also occurs in crystal form.  The crystal form of quartz is the one used most in jewelry.  Quartz doesn’t require much in the way of special care, it will scratch but smaller stones are cheaper to replace than recut.

 Quartz also occurs in a cryptocrystalline form.  Don’t worry about what “cryptocrystalline” means.  These quartzes are agates, jaspers and chalcedonies (pronounced Kalsedonys).  Here I will write about the crystal forms of quartz, the cryptocrystalline quartzes will be discussed in a later chapter.

 

Amethyst     

            Amethyst is a purple quartz that ranges in color from blue violet to almost pink.  It is the traditional birthstone for February.  The name amethyst is from the Greek amethystos, which means “not drunken”.  The Greeks believed that amethyst would keep those who wore it from getting drunk. 

            Throughout history amethyst was an extremely prized stone.  However in the past couple of hundred years its value has fallen because of large deposits being discovered in South America, in the countries of Brazil and Uruguay.  Amethyst today is a common gemstone found in Africa, Canada, Russia, India, America and other localities. 

            Large geodes full of amethyst crystals are found in South America, the geodes are cone shaped and some are over six feet tall.  It is also found in alluvial deposits in riverbeds.  Large stones are common, the large purple stone in the scepter of the crown jewels of Britain is an amethyst.  If you are looking for a large stone for an impressive piece of jewelry an amethyst may fit your needs.

 

Citrine           

            Citrine is a yellow colored quartz which ranges in color from lemon yellow to a deep red-orange.  Much citrine starts out as amethyst or smoky quartz which is carefully heated until it turns yellow.

            Like amethyst, citrine is readily available and often found in large sizes, some over 20 carats.  A large, well cut citrine makes an impressive piece, and the price won’t break the bank.  Because of its color and price citrine is often used as a replacement for topaz, November’s berthstone.  Topaz isn’t as available and is much more expensive, also the color of small topaz is often light and looks “washed out”.

 

The Other Quartz Crystals 

            Rock crystal is clear quartz and is found in crystals weighed in kilos not carats.  It is pretty boring as a jewelry stone and is rarely used.  However many rock crystals contain inclusions of rutile (titanium) or tourmaline.  These inclusions make the stones conversation pieces in carvings and jewelry.

             Smoky Quartz is brown or grey to black in color, radiation causes this in quartz.  There is a rich history in smoky quartz especially the black variety known as morion or cairngorm in Scottland.  It is seldom used in jewelry today.  The brown to grey varieties do not possess desirable color and the black stone has been replaced by black onyx.

             Rose quartz is a pink semi-transparent to opaque stone.  The stone is usually cut into a cabochon (rounded top).  Stones that aren’t cracked and have even color make nice looking jewelry because the stones are often large and the color is a blush of pink, not an overpowering hot pink.