3.5" Andradite Garnets with Hedenbergite and Fluorapatite - China

This is a 3.5" wide cluster of, black, black andradite garnets (Melanite) (Melanite) that formed in association with small, light-green fluorapatite crystals and green hedenbergite, a combination of minerals that are seldom found together. It was collected from Chifeng City in Inner Mongolia, China.

Comes with an acrylic display stand.

Andradite is a species of the garnet group, and although not as well known as some other types of garnets such as almandine or pyrope, it is the most lustrous. There are three varieties of andradite which include melanite (black garnets), topazolite (yellow garnets) and demantoid (green garnets). It occurs in skarns developed in contact metamorphosed impure limestones or calcic igneous rocks; in chlorite schists, serpentinites and in alkalic igneous rocks (typically titaniferous).

Garnets are nesosilicates having the general formula X3Y2(SiO4)3. There are many species of garnet which include pyrope, almandine, spessartine, uvarovite, andradite and grossular (varieties of which are hessonite, cinnamon-stone and tsavorite). Garnets are found in a wide variety of colors including red, orange, yellow, green, purple, brown, blue, black, pink, and colorless, with reddish shades being the most common.

Hedenbergite is a calcium iron (magnesium) silicate that often bears a range of green to brown coloration. The crystals are typically opaque and occur in stubby or prismatic aggregates. Inner Mongolia, Russia and Greece all produce quartz crystals that are green in color as a result of fibrous hedenbergite inclusions. A variety of hedenbergite crystal forms can be found in Sweden as well, with dark-green blocky crystals coming from the Nordmark Odal Field.

Hedenbergite was given its name in 1819 by Jöns Jakob Berzelius, a chemist in Sweden. He named the mineral in honor of Anders Ludvig Hedenberg, a chemistry student and co-worker of Berzelius. Hedenberg is credited with the first documented discovery and description of Hedenbergite in Tunaberg, Sweden.

The general chemical formula of Hedenbergite is CaFe2+Si2O6 .

Fluorapatite is the most common variety in the apatite group. It's known to form early in almost all igneous rock as small, microscopic crystals. It can display a wide variety of colors and can be confused with beryl, phenakite and milarite. Often forming bright, lustrous crystals with hexagonal faces and off-center terminations. They are found in vugs, often associated with quartz and calcite. Most complete crystals are around an inch in length, though larger crystals up to about 4 inches long have been found.


DETAILS
SPECIES
Andradite var Melanite, Hedenbergite & Fluorapatite
LOCATION
Hexigten Banner, Chifeng City, Inner Mongolia, China
SIZE
3.5 x 2.9"
CATEGORY
SUB CATEGORY
ITEM
#182842