AENIGMATITE--THE RIDDLE IS SOLVED

ENIGMA

1. puzzling or inexplicable occurrence or situation

2. person of puzzling or contradictory character

3. a saying, question, picture, etc., containing a hidden meaning

(courtesy dictionary.com)  

As a kid I was not really interested in puzzles or riddles but was a voracious reader.  Unfortunately, I still am not interested in puzzles although friends inform me that they are good for brain health!  Is that true? Don’t know! What I do know is that my reading habits have served me well since childhood and are still a joy today.  My current play list includes a series of books written by the British naturalist Gerald Durrell, rereading River Horse (William Least Heat Moon), and a new bio on Jim Bridger.  In addition, throw in the journals like Rock and Gem and Rock and Minerals as well as a slew of club newsletters.  In a final bit of trivia, Least Heat Moon and I were co-presenters at an undergraduate research symposium and shared a cold IPA together one evening.

My early reading also got me interested in cryptography, and in an enigma, no not a riddle nor the band but a cipher machine used extensively by Nazi Germany during World War II.  These devices used algorithms to code, and ultimately send via wireless, messages to the military units who in turn had an identical machine to read the code and then use a key to decipher.   Very simple encryption might use the key “shift 6.”  So, MJXE could be sent and translated to ROCK as can be seen from shifting letters in the second line.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

V W X Y Z A B C D E F G H I J K L M N O P Q R S T U

Now, the Nazi Enigma Machine was much more complicated than this simple example (termed a Caesar Cipher) and was used extensively to send secure encryptions, top-secret information---or so the Nazis thought.  It turns out that a group of Polish cryptologists, working with British colleagues out of the famed Bletchley Park, “cracked the Enigma cipher” and substantially shortened the war effort (perhaps 2-4 years) and perhaps even “won the war” for the Allies. The code breaking at Bletchley Park remained classified information until the 1970s.

An Enigma Machine at the Imperial War Museum, London.  Photo Public Domain courtesy of Karsten Sperling.

 

Back to my kiddiehood---simple encryptions (Caesar Ciphers) were an important part of our boyhood games.  Each play day the “code” would change from “shift 6 to shift 3” etc. Some days the code would be written with lemon juice and the paper needed heat to allow the juice to turn a brown color so it could be read.  At other times our teachers would use encryptions as a learning tool—the code shift today is (6+3)x2(÷3).  In looking back, I learned much with out the use of computers and other electronic gizmos just as Ralphie did in the movie The Christmas Story—Be sure to drink your Ovaltine coded out on his secret decoder ring. Actually it was a decoder pin and if this mundane bit of trivia confuses you, see the movie.  

 ck to m

But back to the mineral of the day. Aenigmatite was named in 1865 and mineralogists were uncertain of its chemical composition, an enigmatic situation, a riddle.  This ranks very high on my list of the best derived mineral monikers.

Igneous pluton

A rare aenigmatite forms

Rich in sodium

Think I did it---5 syllables first line, 7 the second, 5 in the 3rd. That makes a haiku. Right?

 

Aenigmatite, length of crystal 3 cm. Collected from Mt. Eveslogchorr, Khibiny Massif, Kola Peninsula, Russia.

I purchased this specimen of aenigmatite shown above since: 1) it was a  beautiful prismatic crystal; 2) it was one of those strange, igneous, silica-poor, aluminum-poor, sodium-rich minerals that often occurs with aegirine-augite, astrophyllite, arfvedsonite, riebeckite, hedenbergite, fayalite, and ilmenite in alkaline volcanics and pegmatites.  Good exposures of these rocks occur in exotic localities with unpronounceable names such as the Ilimaussaq intrusion in Narssarssuk, Greenland, and the Khibiny and Lovozero massifs, Kola Peninsula, Russia.  These are places where the average rockhound will lack access for collecting! However, there might be collecting locality closer to home???  MinDat noted (7 December 2021) that aenigmatite was known from the Mt. Rosa Granite (a sodic igneous pluton), part of the greater Pikes Peak Batholith (~1.08 Ga) near Colorado Springs.  Unfortunately, MinDat did not provide photos.  Since Eckle, in his tome on minerals of Colorado (1997), did not recognize aenigmatite from Colorado, I presume the MinDat information came from a thesis by Livingston (2020) who stated, Diverse lithologies are associated with emplacement of the complex; these included peraluminous to peralkaline granitic rocks with several associated minor rock types, such as various dikes and pegmatites. Recent geologic and geochemical studies of the complex revealed the Mount Rosa Granite to have a complex petrogenesis within the pluton. This granite is host to complex Ti-bearing minerals, astrophyllite [K3Fe2+7Ti2Si8O26(OH)5] and aenigmatite [Na2Fe2+5TiSi6O20], which are noted to represent highly peralkaline rocks….At any rate, aenigmatite is a fairly rare mineral found only in these complex alkaline rocks.

Aenigmatite, Na₄(Fe₁₀Ti₂)O₄(Si₁₂O₃₆), is a sodium, iron, titanium silicate with a black to dark brown color and an adamantine to greasy luster.  On first glance, it appears opaque but with a strong back light some crystals are translucent.  The streak is reddish brown while the hardness is ~5.0 to 6.0, call it 5.5. It is quite brittle with an uneven fracture.

The photos on MinDat seems to indicate that most crystals are pretty ugly prisms, often short and stubby, and rough or pitted in appearance.  I was concerned that perhaps my specimen was misidentified until: 1) a MinDat photo of nice shiny, striated and terminated crystal collected from the Azores (Portugal) looks very similar to mine; and 2) Rock Currier, in a MinDat best of article stated “sometimes black, well developed prisms to 10 cm are found (sometimes striated) frozen in the alkaline rocks of the Khibiny Massif… Boots Cureton says he has had specimens from there that were confirmed by microprobe that were sharp bladed, black, prismatic and striated to 4 cm.”  Two labels on my specimen indicate it was collected from Chibiny, Kola Peninsula.  So, I will go with those identifications, and a second enigma was solved! However, I have not come to terms with a third enigma--why line spacings are different within this post ?

As I attempt to finish this post on December 18, I periodically step outside to view the last full moon of 2021.  It is a beautiful sight since the skies are clear and I am able to use trees to mostly obscure city lights.  This final full moon is often termed the “cold moon” for obvious reasons, except this year in Colorado where temps are constantly above normal, and snow has not been recorded this fall/winter.  But my favorite name is “the long night moon” due to the upcoming arrival on December 21^st of the Winter Solstice, the longest night of the year (in the Northern Hemisphere) where in Colorado Springs the sun sits at 4:40 pm and rises on the 22md at 7:14 am.  Since I live on the north side of a “hill” the sun disappears mid-afternoon.  Never-the-less, a full moon and the Winter Solstice---my moments of tranquility and enjoyment.  I looked for Comet Leonard near Venus after sundown but could not really pick it out. Oh well, the full moon was OK for me.   

REFERENCES CITED

Eckels, E. B.,1997, Minerals of Colorado: Fulcrum Publishing, Denver.

Livingston, K., 2020, The Peralkaline Mount Rosa Granite: Contrasting Mineralogy and Geochemistry Observed in the Mount Rosa Granite, Pikes Peak Batholith, Colorado: Masters thesis, Colorado School of Mines). https://mountainscholar.org/handle/11124/176299?show=full