Garnets

Above Inside an almandine garnet.  The bright red colour is typical.  Note the cluster of apatite crystal, including a twinned crystal.  Finally rutile needles aligned with the crystal planes.  These are all features which made it easy to identify this stone as an Almandine Garnet. Click here for larger image, will open in a new tab.
Below a Spessartine Garnet.  The radial inclusions (looking like thin wavy lines) are typical.  The white circle around the gem is part of the lighting I used to take the picture
>Click here for larger image, opens in a new tab.

Everybody knows garnets are red, in fact many other colours can be found - except blue.
Historical evidence suggests garnets were used from 3100BC, and they have remained popular since the 18th century.  Before synthetic ruby was developed, garnet was often used for the bearings in watches.
Chemically they are compound silicates, and come in a number of different formulae. The better stones look great when faceted, while others are given a cabochon shape.
Garnets divide into a number of different types, including Almandine, Pyrope, and Andradite.  Variation in the crystal structure produces these different types.  Differences show in various ways, including the inclusions, colour, refractive index and specific gravity.  However most gems come between the types, and include features of more than one type, therefore they are defined by the most dominant type.
From ancient times garnets have been valued for keeping the wearer safe from harm, and were especially prized by warriors both to protect them from injury, and to give them a feeling of peace and tranquillity.  Curiously, they were also believed capable of inflicting fatal wounds, and in 19th Century Kashmir garnets were used as bullets for attacking British troops.  The ancients believed the wearer would be blessed with good health, and the stone would ward off nightmares.

Caring for Garnets

Cleaning won’t pose any problems, the stones can be safely soaked in warm water, then cleaned with detergent.  These stones are only as hard as silica, which is a main constituent of sand, soil and household dust.  Avoid wearing garnet rings when working, dust will scratch them.