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avatar Borax
June 29, 2009 07:59PM
Click here to view Best Minerals B and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.

Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?

BoraxNa24O7> · 10H2O monoclinic

1.Borax crystals, Boron, California, USA ~7cm across

Borax crystals are likely to be found anywhere borate rich water from hot springs accumulates on the surface of the earth. As the water evaporates, eventually the water becomes saturated and borax crystals will start to crystallize. When all the water evaporates, the Borax crystals will start to dehydrate, loose half their water and become a white mineral called Tincalconite. Because Borax will dehydrate under normal atmospheric conditions and Tincalconite is soluble, these minerals are not very stable and often end up as piles of white powder in collection drawers. They can be preserved in their original state if extraordinary measures are taken. This means the creation of air and moisture tight containers where the humidity and temperature is kept constant. Usually it is much more trouble than it is worth.

Borax has been know for centuries and was originally imported into Europe from Tibet where it was prised as a flux by goldsmiths. Later, large deposits of borates, mostly in the form of Colemanite and Ulexite were found near the end of the 19th century in the USA, most notably in Death Valley, California. This was refined without too much trouble into borax and what ever other borates that were needed. Eventually a big deposit of crystallized borax was discovered at Boron, California and it became cheap enough that it could be offered for sale profitably as a water softening agent. Subsequent to the discovery of crystallized Borax at Boron, a huge deposit of borax was found in Turkey that is reported to be perhaps ten times the size of the one at Boron. It is likely that more deposits containing borax will also be found.

BoraxArgentinaJujuy, Coranzuli, Loma Blanca borate deposit

2.Borax, ~8 cm maximum dimension

Possibly there is some real borax in theses specimens, but more than likely it has all been dehydrated and altered to Tincalconite. We need someone to tell us about this deposit and the Borax specimens found there.

BoraxItalyTuscany, Pisa Province, Pomarance, Larderello

3.Borax crystal on matrix ~1.5cm

The Borax crystal in this picture has just begun to alter to Tincalconite but is mostly still Borax. We need someone to tell us about this locality and the Borax crystals it produces.

BoraxUSACalifornia, Kern Co., Kramer District, boron, U.S. Borax Open Pit Mine

4.Borax xls growing on wood ~15cm wide

5.Borax crystals ~30 cm wide
5.Borax crystals ~15cm wide

7.Borax crystals ~12cm tall
8.Borax altering to Tincalconite ~12cm wide
9.Borax crystals, "hemimorphic" ~5cm wide

Many of the specimens pictured above were taken yeas ago, shortly after they were collected. Certainly they have now altered to white opaque specimens of Tincalconite after Borax. They are all from the old underground mine at Boron, California. These crystals, to some people, are not real minerals, because man had a hand in creating them. These specimens and many more are found growing in sumps and partially flooded stopes in the old underground workings at Boron. Conditions in the underground mine, like most mines, is very stable and the temperatures rarely fluctuate more than a degree or two year round. This provides an ideal setting for the growth of well formed large crystals (crystals of more than 30 cm diameter are known) as the borax saturated water slowly evaporates. Crystals of several different morphologies are found at different places in the mine ranging for prismatic crystals like shown in pictures # 1 & 2 above. Sometimes the crystals are flat and tabular or big and blocky. Somtemes they are bladed and pointed like #9, although this is not a particularly fine example of this type of specimen. Anything that is thrown or falls into the borax saturated water will provide a handy matrix upon which crystals will form. Picture 4 shows a beautiful cluster of prismatic Borax crystals growing on some wood. Sometimes the crystals are almost white and colorless, but often slight impurities impart an amber color to the crystals. Upon exposure to air, they eventually all turn white. Picture 8 shows a Borax specimen in the process of altering to Tincalconite. Borax saturated water outside of the stable conditions of the underground mine sometimes produce borax crystals as they evaporate, but because of the daily fluctuating temperatures, the crystals are usually not well formed or very large.

At one time the underground mine at Boron was the largest underground operation in California with more than 200 miles of underground tunnels and stopes. The underground mine accessed the ore body predominately through three shafts, the Old Baker shaft, the furthest east, the Jenifer shaft and the most western shaft the West Baker shaft. All of these shafts and mines with the same name were eventually all connected underground and all worked the same ore body. Most of the borax crystals that were produced from the underground were mostly from the West Bake mine though some were produced from the old Baker mine. Eventually because of economic considerations, it was decided to open pit the deposit. At various times, large quantities of Borax crystals from have been collected from the sumps and partially flooded stopes of the old underground mine. Sometimes the mining company permits the collecting of these borax crystals, especially to assist the local gem and mineral society for their yearly gem and mineral show and auction. The collecting of these specimens has to be among the easiest and most fun of all mineral collecting endeavors. Because of the large size of the underground tunnels at Boron, you can actually drive into the mine and right up to the stope or sump where the crystals are located. The procedure is to wide into the partially filled stope and start banging the specimens out. Usually the water is less than three feet deep and very transparent, at least initially until you stir up the dust that has accumulated on the bottom of the stope/pond. You can see the crystals lining the walls and bottom of the stope and growing on anything that has been thrown or fallen into the stope. A few taps with a chisel is usually enough to free the specimens from their matrix. You spend a lot more time walking these specimens back to the edge of the stope and wrapping them than you do collecting them. After the water gets turbid you have to feel around with your hands to locate the good specimens and free them from the walls etc. It is always exciting to pick them up out of the turbid water to see the latest treasure. The crystals and especially the broken edges of crystals are very sharp and you can cut yourself easily. However you generally don't feel it because the borax solution does not sting like salt water, and the borax solution seems to act like an antiseptic and the cuts rarely become infected. Some of these Borax specimens have been traded for fine specimens. One particular trade I recall I wish I had made was for a very fine Glove wulfenite specimen.

Here is an interesting description by mine geologist Joe Siefke who collected a lot of outstanding Borax specimens from the underground section of the mine at Boron: In 2001 I had an opportunity to collect (now) tincalconite specimens from the Baker mine "C" level stopes as Redpath miners were clearing out timber & metal in preparation for final closure. That episode definitely marked the close of underground collecting. In subsequent years, the mine conducted campaigns of deep ore pillar blasting to ensure safe pit bench operations. A couple of years after I collected the Baker crystals & groups, after they had turned thoroughly white, I 'stabilized' the specimens by immersion in a bath of pure S&F acryllic floor wax, following what Dave Eyre recommended. The specimens appear have held up quite well. Joe further commented in a subsequent email that Redpath is an international underground mine contractor (google: redpath). The specimen in the visitor center is approx. 20 in. in greatest dimension. I collected 200 tincalconite specimens, about half singles & half clusters. The singles range is 2" - 6"; mostly 'blocky'/ few thin pencils. The clusters are 2x2" to 6"x8". The clusters & large singles are bubble wrapped & stored in sealed rubbermaid trays.

The reason that the miners were cleaning out the timbers and metal is because the open pit mine was going to expand into that area of old underground mining and the company did not want mine timbers and metal to screw up their crushers and ore processing facilities. The reason for the subsequent drilling and blasting of that section of the mine is because they wanted to collapse the old working in this part of the mine, so that when the heavy equipment mining that area in the open pit would not suddenly collapse into old underground workings. This had happened in the past.

Click here to view Best Minerals B and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.

Rock Currier
Crystals not pistols.

Edited 8 time(s). Last edit at 03/24/2012 10:57AM by Rock Currier.
jaime A.
Re: Borax
September 28, 2009 11:50AM
Hello Rock Currier:

I would like to get a hold of you in order to negotiate the use of some photographic material from this page. how can i reach you? We have urgency since this is for a museum soon to be inaugurated.

thank you
avatar Re: Borax
September 28, 2009 12:24PM
You can reach me at But before I do any negotiations I will need to know exactly who you are and what you want the images for.

Rock Currier
Crystals not pistols.

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