Usually colorless, may be very pale green depending upon mineral's iron content. return; These varieties of rocks are maximum not unusual at divergent plate limitations and at hot spots within the centers of tectonic plates. if (gAutoPrint) We also wanted to look at some interference colors produced by olivine. { html += headTags[0].innerHTML; Optic Sign & 2V Massive - Granular - Common texture observed in granite and other igneous rock. var html = '\n\n'; else if (printReadyElem != null) This is a grain seen in plane light, with both the cleavage and the elongate direction of the mineral aligned with the cross-hairs: We then crossed the polarizers and saw that the mineral was extinct when the cleavage planes were parallel with the cross-hairs: Optical properties of small particles of olivine (less than 0.1 μ) have been studied in the ultraviolet as an example of an insulating solid. The common Mg-dominant member of the group was renamed forsterite by Serve-Dieu Abailard "Armand" Lévy in 1824. Olivine is named for its typically olive-green color, thought to be a result of traces of nickel, though it may alter to a reddish color from the oxidation of iron. } var printWin = window.open("","printSpecial", 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=yes,width=350,height=350'); Olivine continued to be used, as either a species, a series, or as a group, for over a century afterward. • Interference colors: Strong, III order colors. distinct habit are rare. By turning the microscope stage by 45 degrees, we saw that the light being transmitted by the mineral was at a maximum: Sign of Elongation document.write('dbarthelmy@webmineral.com<\/a>'); } Exceptional Minerals Just what we were looking for: (n=1.635) Translucent olivine is sometimes used as a gemstone called peridot (péridot, the French word for olivine). var headTags = document.getElementsByTagName("head"); alert("Could not find the printReady section in the HTML"); { PROP. var printReadyElem = document.getElementById("printReady"); It is the only common igneous mineral with these properties. if (document.getElementsByTagName != null) } That makes it one of the first minerals to crystallize from a magma. Based on 0 rating (s) Name. Hudson Insitute sign of elongation. alert("Sorry, the print ready feature is only available in modern browsers. Link to , Calcio-olivine - calcium-dominant member of the olivine group, a = 4.78, b = 10.25, c = 6.3, Z = 4; V = 308.67 Den(Calc)= 3.30. The oil and mineral now match, and we know this because instead of having the white Becke lines, the light is splitting into the yellow and blue fringes visible in the image above. DFT-investigation on anisotropy degree of electronic, optical, and mechanical properties of olivine ZnRE 2 S 4 (RE = Er, Tm) compounds M Batouche 1 , T Seddik 1,6 , S Uğur 2 , G Uğur 2 , S Messekine 1 , Tuan V Vu 3,4,6 and O Y Khyzhun 5 John Betts Fine Minerals Optical Properties: • Form: Six sides circular section on (001), rectangular section on (010), six or eight sides section elongated on c in (100) section. • Color: Colorless or pale green-yellow with increasing Fe. (Dana) OPTIC PROP. Photomicrograph of olivine in plane light. By looking at the distance between the two isogyres, and knowing the width of the field of view (in degrees), we can make an estimate for how far apart the isogyres are, which is the 2V. Olivine is in many ways similar to clinopyroxene. } However, it is very hard to get the necessary interference figure from a biaxial mineral which is good enough to be photographed. Optical Data: Biaxial (+), a=1.63-1.65, b=1.65-1.67, g=1.67-1.69, bire=0.0400, 2V(Calc)=88, 2V(Meas)=46-98. (Dana). It usually crystallizes inside the presence of plagioclase and pyroxene to form gabbro or basalt. Rock and Mineral Shows Photomicrograph of olivine under crossed polarized light. Mineral Discussion Forum from Fabre Minerals - also available in The colour of any object is a light dependent property- it is the appearance of the particular object in light (darkness destroys colour). © Fabre Minerals. Color: Green Yellow Colorless: Hardness: 6.5: Specific gravity: 3.2 (forsterite) 4.4 (fayalite) Cleavage: Poor (010) and (100) Fracture: Conchoidal: Luster: Vitreous: Transparency: Transparent to translucent: Streak: White (forsterite) White-yellow (fayalite) Optical Properties: PPL: High relief Cleavage. The layers consist of octahedrons cross-linked by independent SiO 4 tetrahedrons. It is a common rock-forming mineral. Cleavage. Goup species name. We know that the mineral now has the higher refractive index because the Becke lines move into the mineral when we move the stage. The properties of these absorptions vary with composition, enabling compositional analysis of olivine through VNIR spectroscopy, both in the laboratory and through remote sensing. Very little structure survives in the … printWin.document.open(); Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. Colour: . First, we picked an oil which had too high a refractive index to match the olivine grains: Olivine (thin section) Type. Refractive Index Excalibur Minerals } Then we chose an oil which had too low an R.I. Calculated Properties of Olivine : Electron Density: Bulk Density (Electron Density)=3.25 gm/cc note: Specific Gravity of Olivine =3.30 gm/cc. { It is transparent to translucent with a glassy luster and a hardness between 6.5 and 7.0. The structure of olivine can be viewed as a layered closest-packed oxygen network, with silicon ions occupying some of the tetrahedral voids and the calcium, ferrous iron, and magnesium cations occupying some of the octahedral voids (Figure 2). html += '\n\n'; printWin.document.close(); Optical Properties of Olivine. Olivine has a totally high crystallization temperature as compared to other minerals. Mag. we see that aragonite is optically negative. Olivine typically displays pale green pleochroism and no distinct cleavage. Most olivine found at Earth’s floor is in dark-colored igneous rocks. Usually colorless, may be very pale green depending upon mineral's iron content.