Lazurite and Phlogopite

ID	112
Mineral	Lazurite Phlogopite
Location	Ovalle - Coquimbo - Chile
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Lazurite information at mindat.org View Phlogopite information at mindat.org

Mindat data

ID	2357
Long ID	1:1:2357:9
Formula	`Na₇Ca(Al₆Si₆O₂₄)(SO₄)(S₃)^1- · H₂O`
IMA Status	0
General Appearance	Velvet Lazurite of Sapozhnikov et al (2021)
Occurrence	The Malo-Bystrinskoe lazurite gem deposit, Baikal Lake area, Eastern Siberian region, Russia.
Other Occurrences	Contact metamorphic mineral in marble and skarns. Also in some syenites and alkaline volcanics.
Industrial	The blue mineral in Lapis Lazuli, an ornamental stone
Discovery Year	1890
Diapheny	Opaque
Cleavage	Imperfect on {110}
Tenacity	brittle
Colour	Ultramarine, midnight blue, bluish green, green
Hardness (min)	5.0
Hardness (max)	5.5
About the name	From the Persian "Lazhward" for "blue." Also for its dark blue color resemblance to "azurite." Both Lazurite and azurite derive from "Lazhward". Dana (System of Mineralogy, 1868) considered lapis-lazuli to be the dark blue mineral in the lazulite-calcite rock of the same name, but these were renamed lazurite in 1891 [[1\| Brögger W C, Bäckström H 1891]].
Streak	Bright blue for lazurite, white for the small cell hauynes.
Crystal System	Isometric
Cleavage Type	Imperfect/Fair
Fracture type	Sub-Conchoidal
Morphology	Dodecahedrons, cubes, granular, disseminated, massive.
Twinning	None observed
UV	The opaque ultramarine and midnight blue Lazurites are not fluorescent. The translucent green and blue hauynes have an orange brown fluorescence under Long Wave UV.
shortcode_ima	Lzr
Group	Sodalite Group

ID	2815
Long ID	1:1:2815:4
Formula	`KAl₂(Si₃Al)O₁₀(OH)₂`
IMA Status	0 1
Other Occurrences	Muscovite is common in many different rock types as a primary mineral.
Diapheny	Transparent,Translucent
Cleavage	Perfect on {001}.
Tenacity	elastic
Colour	White to colorless, silvery-white, and tinged various colors by impurities.
Hardness (min)	2.5
Hardness (max)	2.5
About the name	The earliest names attributable to muscovite include Muscovy Glass, Cat Silver, and Lapis Specularis (stone mirror); these names appearing in texts in the seventeenth century and before. The stand-alone name 'Muscovite' was used as early as 1794 by Johann Gottfried Schmeisser in his System of Mineralogy and is derived from the term "Muscovy glass," which was in common use by that time. Muscovy Province in Russia yielded sheet mica for a variety of uses. Muscovite and sometimes similar species were earlier called mica (Phillips and Kersey, 1706), glimmer (Phillips and Kersey, 1706), and isinglass (1747 according to OED) but all of these terms are still in use to some degree. It should be noted that mica, glimmer, and isinglass were also used for a variety of materials before these given dates and in those earlier times did not always indicate what would be a mineral, much less muscovite proper. Isinglass, for example, was originally used for a gelatinous bladder found in sturgeon.
Streak	White
Crystal System	Monoclinic
Cleavage Type	Perfect
Fracture type	Micaceous
Morphology	Crystals uncommon, tabular {001} with rhombic to hexagonal outlines, often bound by {221}, {_111} and {010} (hkl refer to -2M^1 polytype). Less common as prismatic, parallel to [001], with a crude hexagonal cross section. Most typically found as "books" and as flaky grains in various rocks. Sometimes in plumose or fibrous aggregates.
Twinning	Mica law twins common [310] forming six pointed stars, less common with the composition plane perpendicular to {001} (hkl refer to -2M^1 polytype).
shortcode_ima	Ms
Group	Dioctahedral mica

Price: € 5

Dimensions: Not registered

Weight: Not registered

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Notes:

Symbol	Element
Al	Aluminium
Ca	Calcium
H	Hydrogen
K	Potassium
Na	Sodium
O	Oxygen
S	Sulfur
Si	Silicium

Lazurite and Phlogopite

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