Garnet is a group of closely related mineral species. They share the same crystal structure but differ in chemical composition.
In more detail
Five species are important as gems: pyrope, almandine, spessartine, grossular and andradite. Many garnets are chemical mixtures of two or more species. Garnets come in almost every color, and some show a color change like alexandrite. Garnet is rarely treated; when it is, the treatment is fracture filling. Steam cleaning is not recommended.
Related terms
- Pyrope: Pyrope is a garnet species made of magnesium, aluminum and silicon. It is usually pink to orange-red or brown.
- Almandine: Almandine is a garnet species made of iron, aluminum and silicon. It is typically brownish to purplish red.
- Spessartine: Spessartine is an orange garnet species made of manganese, aluminum and silicon. Its hues are warm: yellow, orange, red or brown.
- Grossular: Grossular is a garnet species made of calcium, aluminum and silicon. It has perhaps the widest color range of any garnet species.
- Demantoid: Demantoid is the green variety of andradite, a garnet species of calcium, iron and silicon. Chromium causes its color.
- Color change: Color change is a visible change of a gem's main hue between daylight and incandescent light.