Calcite, Titanite and Pyrite

ID	326
Mineral	Calcite Titanite Pyrite
Location	Naica - Chihuahua - Mexico
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Calcite information at mindat.org View Titanite information at mindat.org View Pyrite information at mindat.org

Mindat data

ID	859
Long ID	1:1:859:4
Formula	`Ca(CO₃)`
IMA Status	0 1
Other Occurrences	Found in most geologic settings and as a later forming replacement mineral in most other environments in one form or another, it is most common as massive material in limestones and marbles. It forms as chemical sedimentary deposits as limestone, can be regionally or contact metamorphosed into marbles and rarely forms igneous rocks (carbonatites). Also is a common gangue mineral in hydrothermal deposits.
Industrial	Mined extensively for a wide variety of uses ranging from lime (cement) to limestone and marble building stones and aggregates, agricultural supplements and optical calcite.
Diapheny	Transparent,Translucent
Cleavage	Perfect on {10_11}.
Tenacity	brittle
Colour	White, Yellow, Red, Orange, Blue, Green, Brown, Gray etc.
Hardness (min)	3.0
Hardness (max)	3.0
Luminescence	Fluorescent
Lustre	Vitreous
About the name	Ancient name. Named as a mineral by Gaius Plinius Secundus (Pliny the elder) in 79 from Calx, Latin for Lime.
Streak	White
Crystal System	Trigonal
Cleavage Type	Perfect
Fracture type	Conchoidal
Morphology	Over 800 different forms have been described. Most commonly as acute rhombohedrons or prismatic with scalenohedral terminations, or combinations of the two.
Twinning	At least four twin laws have been described, the most common being when the twin plane and the composition plane are {01_12}. Also common with twinning on {0001} with {0001} as the compositional surface, producing re-entrant angles. Uncommon with {10_11} or {02_21} as twin planes, producing somewhat heart-shaped crystals ("butterfly" twins).
UV	May be fluorescent under LW UV, mid-range UV or SW UV as well as under X-rays, cathode rays and even sunlight, in a number of colors and shades, commonly an intense red under SW with Mn as an activator (such as at Franklin, New Jersey, USA, and Långban in Sweden.
Comment Luster	Pearly on cleavage and {0001}. Can be dull or earthy in chalk variety.
shortcode_ima	Cal
Group	Calcite Group

ID	3977
Long ID	1:1:3977:8
Formula	`CaTi(SiO₄)O`
IMA Status	0 1
Other Occurrences	Common accessory mineral in intermediate and felsic plutonic rocks, pegmatites, alpine veins. Also in some gneisses, schists, and skarns.
Discovery Year	1795
Diapheny	Transparent,Translucent
Cleavage	Good on {110}
Tenacity	brittle
Colour	Brown, green, yellow, orange, rose-red, black, beige, grey, colourless, grey-blue, bluish
Hardness (min)	5.0
Hardness (max)	5.5
Lustre	Adamantine to resinous
About the name	First recognized as "nouveau substance minérale" in 1787 by Marc August Pictet, but only described and named in 1795 by Martin Klaproth for its titanium content. A common synonym, sphene (from the Greek sphenos (σφηνώ), meaning wedge, for its common wedge-shaped crystals), was introduced in 1801 by Rene Just Haüy.
Streak	White
Crystal System	Monoclinic
Cleavage Type	Distinct/Good
Morphology	Common forms are {111}, {110}, {102}, {100}, {001} and {112}. Crystals equant to wedge-shaped, or flattened with large {001} or {102}, or prismatic by extension along [001], to 65 x 17 x 17 cm, compact, massive. NOTE: The morphological data is based on a choice of unit-cell parameters that differs from the one that is given in Mindat. This 'old' unit cell has a = 6.56, b = 8.72, c = 7.44 Å and β = 119.54° (see the introduction in http://rruff.info/rruff_1.0/uploads/AM61_238.pdf). The 3D drawings of titanite are also based on this old cell.
Twinning	On {100}, contact and penetration, less commonly lamellar on {221}.
key_elements	0
shortcode_ima	Ttn
Group	Titanite Group

ID	3314
Long ID	1:1:3314:1
Formula	`FeS₂`
IMA Status	0 1
Other Occurrences	Common in many rock types, igneous, metamorphic and sedimentary.
Diapheny	Opaque
Cleavage	Indistinct on {001}.
Tenacity	brittle
Colour	Pale brass-yellow
Hardness (min)	6.0
Hardness (max)	6.5
About the name	Named in antiquity from the Greek "pyr" for "fire", because sparks flew from it when struck with another mineral or metal. Known to Dioscorides (~50 CE) under the name "περι υληζ ιατρικηζ" which included both pyrite and chalcopyrite.
Streak	Greenish-black
Crystal System	Isometric
Cleavage Type	Poor/Indistinct
Fracture type	Irregular/Uneven,Conchoidal
Morphology	Typically cubic or pyritohedral (pentagonal dodecahedral), sometimes octahedral and combinations are common, resulting in striated faces. Less frequently octahedral, most commonly massive, granular, and sometimes radiating, reniform, discoidal or globular.
Twinning	On [110], interpenetrating ('Iron Cross Law'). Twin axis [001] and twin plane {011}, penetration and contact twins. Twinning on (111) was described by Nicol (1904), Goldschmidt and Nicol (1904) and Gaubert (1928), all of whom considered it rare.
UV	Not fluorescent in UV
Thermal Behaviour	Heated in a closed tube gives a sublimate of sulfur and a magnetic residue.
shortcode_ima	Py
Group	Pyrite Group

Price: € 20

Dimensions: Not registered

Weight: 76 g

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Notes:

Symbol	Element
C	Carbon
Ca	Calcium
Fe	Iron
O	Oxygen
S	Sulfur
Si	Silicium
Ti	Titanium

Calcite, Titanite and Pyrite

Mindat data

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