Growth of Broad Linewidth Ruby Crystals

Abstract

Progress has been achieved in perfecting the technique for the growth of ruby from flux and broadening the fluorescent linewidth by Ga additions. Line broadening was achieved in flux-grown ruby crystals both by the deliberate addition of Ga and by the substitution of O2− by F− during crystal growth. Broadening in excess of 10 cm−1 was obtained due to a combination of these factors. Solubility of pure Al2O3 in PbF2 was found to be reduced about 10% by the addition of 0.02 mole % Cr. Chemical analysis of the crystals shows a concentration gradient exists for Cr but not for Ga.

A venture into the interior of natural diamond: genetic information and implications for the gem industry

“…B10 -12: Thermally altered inclusions. Pictures 1 by M. Glas,[2][3][4][5][6][7][8][9][10][11][12] nb: I = immersion Two sapphires with unusual properties deserve separate description: l The first stone ( Figure 20a) was diffusiontreated by J. Emmett and shows a weak colour zoning after proper orientation in the immersion microscope ( Figure 20b). The coloration of the sapphire consists of somewhat lighter and more intense yellowish-orange zones parallel to rhombohedral growth planes.…”

“…C10 -12: Thermally altered inclusions. Pictures 1 by M. Glas,[2][3][4][5][6][7][8][9][10][11][12] nb: I = immersion Figure C11: 50 x Figure C12: 50 x ( Figure D6). No characteristic inclusion feature that would easily allow a distinction between simply heat-treated and diffusion-treated Sri Lankan sapphires was found.…”

“…I12: Thermally altered 'boehmite needle'. [3][4][5][6][7][8][9][10][11][12] nb: I = immersion, # pol. = crossed polarisers Figure I1: I, 0.34 to 0.53 ct Figure I2: I, 0.38 to 0.57 ct Figure I3: I, 0.38 ct Figure I4: I, 40 x Figure I5: I, 40 x # pol.…”

“…Therefore, although ruby can be thought of as 'red sapphire', its name was used long before the similarities of its characteristics with those of sapphire were realised and made public. Many crystal growth techniques, including Verneuil, Czochralski, hydrothermal, vapour phase and flux [2][3][4][5][6][7][8][9][10][11] have been utilized successfully to synthesize ruby single crystals. Among these techniques, the flux growth is very convenient and can produce ruby crystals at temperatures well below the melting point of the solute.…”

“…Most ruby crystals grown from these fluxes are thin hexagonal plates with well-developed {0001} faces. [4][5][6][7][8][9] In flux growth using the temperature-gradient method, Na 3 AlF 6 and Na 3 AlF 6 -Li 3 AlF 6 were employed as solvents. 10,11 The grown crystals displayed faces in the forms {0001}, {2243} and {1011}.…”