Today, we will learn minerals group related to garnet with specifically focusing
on anthill garnet gemstone Arizona. The unique part of Arizona Anthill Garnets is this that they are found around the Ant Hills. Anthill Garnets are also called Arizona Chrome Pyrope Garnet. They are found or come from Navajo Reservation in Arizona, USA. They are also famous for many names such as Chrome Pyrope, Pyrope, Ant Hill Garnet, Arizona Ruby. Among all of them, Ant Hill Garnets is the most interesting name which fits the stones much better than the others. The reason behind this name is very interesting. They are given the title of ” Anti Hill Garnets” because they are found around the ant hills.
The ants excavate the garnets from underground passages. The ants take the stone to the surface and discard them. The weather affects the stones like rain, air and others related factors.
Especially, rain washes the stones and pushes them towards down from the ant hill. They keep on gathering there. This cycle goes on. Exactly, as you see in sedimentary rocks formation or process. But in the case of sedimentary, the rocks have pressure when sedimentary rocks accumulate. In anti hill garnets case, the rain and air make them look like tumbled stones. They are gathered in a small amount. Sedimentary rocks accumulation is a massive process. The garnets get excellent lustre due to natural grinding by rain or other factors. Even in this form, they are ready for beading.
Let us have a look at garnet first before going into further details.
1- Garnet A group of Gems Mineral
Garnets are not single gem mineral. It is a group fo several close minerals. Garnets have many colours and varieties. The popular garnet colour is deep red. In garnet, there are 5 species groups. They are an interesting group involved in the rock formation. Why several minerals are in one group because they share a common crystal structure. Their chemical composition is X3Y2(SiO4)3. In this composition, X is unique and replaceable. It can be Ca, Mg, Fe2+ or Mn2+, and “Y” can be Al, Fe3+, Mn3+, V3+ or Cr3+.
Garnets are found all over the world in three types of rocks like igneous, metamorphic and sedimentary. However, most of the material take forms very near to the surface of the Earth. Rocks like “Shale” which are subjected to pressure and heat, produce schist or gneiss. Shale is a sedimentary rock with aluminium. Garnet is also found in the metamorphic rocks or substance. Garnets have many colours. Most people mistake garnet associated with the red colour only.
Type of Garnets
Technical Information of Garnet Stone
|Formula||X3Y2(SiO4)3. In this composition, X is unique and replaceable. It can be Ca, Mg, Fe2+ or Mn2+, and “Y” can be Al, Fe3+, Mn3+, V3+ or Cr3+|
|Color||Red, Red like ruby, orange, pink, grey, Green, Yellow, Orange, Brown, Purple,|
|Hardness||6.5 to 8.5|
|RI||1.780 – 1.889|
|SG||3.5 to 4.3|
|Transparency||Transparent to translucent|
|Cleavage||None. May exhibit parting.|
Anthill garnets are basically pyrope garnet. Their colour is red like a ruby.
2- Characteristics of Ant Hill Garnet Stone
- Hardness: 7.25
- Structure: Cubic
- Hardness: 7.25
- S.G: 3.8
- R.I: 1.72
- Doubly Refracting or bi-refraction: no
3- Where Anthill Garnets are found?
Pyrope garnets or AntHill Garnets are found in Navajo Indian Reservation, McKinley Co., New Mexico, USA. This place is the home of Native Americans, Navajo and Hopi Indians with having more alluring scenery in the world. This area has gem quality garnets from the underlying intrusive rock. Garnets can be found in all area around the valley.
The Native Americans discovered these garnets many years ago. The stone has a special place for the Native Americans. They love the stone due to its bright colour, high saturation and quality. Native Americans used to collect the garnets and make money after selling them at attractive prices. Though the valley had many other garnet gems and mineral for sale also. The anthill garnets hold a special place due to ants mining. The garnets come in small sizes. Hardly any stone comes over 1 carat. 10000s of stones have been picked and cut for jewellery and sold around the world.
4- How Anthill Garnet Gemstone gets their formation?
The anthill garnet gemstone is not made or produced
commercially in the factories. Neither it is mined commercially. Rather, these garnet stones are mined by the ants. Their miners are ants. This is the interesting thing about ant hill garnets. The ants remove them from the ground, excavate like a miner. But their main purpose is to build or repair their homes. They build their hills. During building their hills or homes, they leave the remainings for humans to collect them. Humans pick the remaining which are in form of ” Anthill garnet”. These are the wastage of ants whereas they are precious for humans.
Ants are very interesting. They are the architecture of their homes. They are home builders. Ants are very strong. They are soldiers also. You can see how they take the heavyweight garnet stone (than them), mine it, or excavate and threw the stones out of their homes on the ground or surface of the earth. They are powerful and more interesting indeed. This is the point which people like about anthill garnets.
Colour and Shape of the Stone
90% of the garnet material has the red ruby like colour. Some other garnets are also found in this area like rhodolite and spessartite garnets. In the fine shape process, rain or environmental factors take place. Continuous raining change the gem quality garnets in the polished tumbled stones. The hue, colour and saturation of the stone are outstanding. These gemstones are popular among locals a lot. Garnet is a semi-precious stone. It is not the garnet for which this stone is famous. Rather it is because of the background story of the pyrope garnets, which make it quite unique.
Gemstones with Unique Background Other Than Ant Hill Garnets
This is also not necessary that only these garnet gemstone has such an interesting story of mining. There are many other stories of rocks and minerals which have like wise popular story behind them. Another example is diamond. Geologists or mineralogists find pigments or indicator minerals which tell us that there would have been a prospective stone which they will be searching for. Diamond is usually found on or near kimberlite pipes which is the host rock of many diamond deposits. Deep Volcanic Eruption causes the diamonds’ appearance on the surface from the mantle. They are only a few in a large quantity of kimberlite. But kimberlite is also containing other gems mineral deposits such as garnet, pyrope. Similarly, in Arizona, geologists or collectors look at ant hills to find garnets.
Geologist or mineralogist and now rock-hounding professionals look for an indicator of minerals such as pigments, host rocks or ant hills. Where they find the desired gemstones reserves or deposits.