http://www.mindat.org/msgboard-74.html Wed, 25 Nov 2009 22:04:17 +0000 Phorum 5.2.8-RC1 http://www.mindat.org/forum.php?read,74,143703,143870#msg-143870 http://www.mindat.org/forum.php?read,74,143703,143870#msg-143870 Rock Currier Best Minerals H Sat, 04 Jul 2009 10:54:53 +0000 http://www.mindat.org/forum.php?read,74,143703,143703#msg-143703 http://www.mindat.org/forum.php?read,74,143703,143703#msg-143703


Hydroboracite
CaMg[B₃O₄(OH)₃]₂· 3H₂O monoclinic

1.Hydroboracite & Colemanite, Boron, Californian, USA ~13cm wide	©

Hydroboracite is a somewhat rare borate mineral, but in some places it is part of the ore in borate deposits that is mined for industrial purposes. Good specimens of it however are not common and in fact good specimens of it are rare. Perhaps the best specimens of it have been produced at Boron, California and the Thompson Mine in Death Valley. The yellow Hydroboracite from the Inder deposit in Kazakhstan is also a strong contender, but I don't know if it got any better that the specimen shown below. Mindat currently lists 36 localities and crystals to 10 cm are known in fan like to radial spherical aggregates and in swallowtail composites.¹ I have never seen any 10 cm crystals of this mineral, and think that about the largest freestanding crystals may be two or three cm.
1. Handbook of MIneralogy, Anthony, Bideaux, Bladh & Nichols, Vol V p304.
[Rock Currier 2009]


Hydroboracite
Germany
Thuringia, Harz Mts, Nordhausen, Niedersachswerfen, Kohnstein Quarry

2.Hydroboracite, FOV 1cm	© Elmar Lackner

Free standing Hydroboracite crystals have been found the Kohnstein Quarry in a series of small pockets in massive Anhydrite. Other well crystallized borates, most notably world class Probertite crystals have also been found there, but of the borates found there the most abundant is Hydroboracite but good specimens are not common. The Kohnstein Quarry, Niedersachswerfen, is an anhydrite quarry mined several years for anhydrite and now inactive.
[Thomas Witzke 2009]


Hydroboracite
Iran
Zanjan Province, Dandy District, Gharah Gol Boron Mine

3.Hydroboracite, FOV 5.5cm	© Maziar Nazari

We need someone to tell us about this locality and the Hydroboracite and other minerals it produces.


Hydroboracite
Kazakhstan
Atyrau Oblysy (Atyrau Oblast'), Atyrau (Gur'yev), Inder B deposit and salt dome

4.Hydroboracite, 6.5cm wide	© Rob Lavinsky

I have seen only a few specimens of Hydroboracite from this locality and most of them were not the nice bright lemon yellow color shown in picture 4. Most were white and looked like the Hydroboracite from the US localities. We need someone to tell us about the Hydroboracite specimens from the Inder deposit.
[Rock Currier 2009]


Hydroboracite
Turkey
Marmara Region, Balikesir Province, Bigadiç, Bigadiç Mine

5.Hydroboracite, FOV 2cm.	© GiovanniFraccaro

6.Hydroboracite, 10cm wide	© Arliguie M

7.Hydroboracite, FOV 7mm	© 2008 Jesse Crawford

We need someone to tell us about the Hydroboracite from the various Turkish borate deposites.


Hydroboracite
USA
California, Inyo Co., Death Valley, Boraxo Mine (Kern Borate; Boraxo Deposit; Boraxo No. 1 and No. 2; Clara Claim; Thompson Mine; Tenneco Mine)

8.Hydroboracite, ~20cm wide	©

9.Hydroboracite ~5cm wide	©

10.Hydroboracite FOV 1cm	© 2008 Jesse Crawford

Most of the good Hydroboracite specimens in collections today, especially in the USA come from the old underground Thompson mine workings before the deposit was open pitted. Most of them were collected by Jim Minette who was the Mine Manager for the big open pit mine at Boron, California. Probably the best best and largest specimens from this find is shown in picture 8 above. Wonderful big blocky Colemanite specimens were taken from this deposit when it was openpitted, but no more Hydroboracite was found.
[Rock Currier 2009]


Hydroboracite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine

11.Hydroboracite and Colemanite ~7cm	©

12.Hydroboracite FOV 2mm	© O. Dziallas

Two types of Hydroboracite specimens have been found at Boron. Perhaps the best specimen is shown in picture 1 at the top of the article. These are almost always associated with the typical sharp white pointed bladed Colemanite crystals that are commonly found at Boron. Probably fewer than ten good specimens have been found. The second type which is more common are tiny white micro crystals of no more than a mm that are associated with little flat bladed Tunellite crystals. We will eventually have a picture or two of this type placed here.
[Rock Currier 2009]]]> Rock Currier Best Minerals H Fri, 03 Jul 2009 08:55:50 +0000 http://www.mindat.org/forum.php?read,74,129400,129400#msg-129400 http://www.mindat.org/forum.php?read,74,129400,129400#msg-129400
Ideally what we want to know about each significant mineral from each locality is:

1. What is the largest crystal of the mineral that the locality has produced?
2. What do the best specimens from this locality look like and where can one be seen?
3. Does the locality produce a variety of different kinds of specimens of this species, and what do the best of each type look like and how many of them were found etc.
4. What are the associated minerals found with this species and what is its geological setting?
5. How abundant are these specimens and when were they found? A type locality? In other words, how rare are they.
6. How do they compare to other specimens of the same mineral from other localities?
7. How much is it worth. This should probably be optional, but in cases where specimens are worth thousands of dollars we should probably say something of the value of these things.
8. What kind of care and feeding do these specimens require? Are they delicate, radioactive, unstable, color changeable etc.?
9. Are the specimens commonly faked, and if so, how to tell if they are?
10. Are there any interesting stories relating to the collecting of these specimens or their discovery as a new mineral?

Of course this is in reality impractical, but if we keep these questions in mind, we will do a lot better job when writing about them.]]> Rock Currier Best Minerals H Fri, 06 Mar 2009 11:16:36 +0000