Garnets with calcium in the X site are referred to as the ugrandite group. Those with aluminum in the Y site but no calcium in the X site are referred to as the pyralspite group. Garnets occur in every color imaginable and are found in most metamorphic and igneous environments. They are very hard and often are gemmy, making for wonderful gemstone rough. Their hardness combined with their natural abundance also makes them very useful in industry.
Garnets are popular because they are abundant, found in many varieties and can be very affordable or very exclusive depending on the variety. There is a species of garnet for every collector and it is a mineral that is so in habit, color, and locality of origin that it is a perfect theme for a specialized collection. Garnet is January’s birthstone and is very popular in jewelry since it is commonly very gemmy and always very hard. Garnet has been known since ancient times as a semiprecious stone- it is a st
Garnets are isometric, with usually 12 (dodecahedral) or 20 (trapezohedral) faces. They also may have a multitude of secondary faces adding to their complexity. Some rare garnets can also have an octahedral or cubic shape. Garnet group minerals typically have a high hardness of 6 to 7.5 on the Moh’s scale. They tend to be on the higher side of this range and are often industrially exploited for their hardness as industrial abrasive.
What is Quartz?