After this ruby grew, it was exposed to high pressure, causing certain planes of atoms to glide into a twinned position. This secondary “polysynthetic” twinning takes place along the rhombohedron faces and is common in many corundums. Twin planes cross at 86.1 and 93.9° angles.
Natural Ruby • Thailand/Cambodia • Enhancements: Heat (H) • Lighting Conditions: Diffuse Light Field + Crossed Polars
Photographer: Richard W. Hughes •
Image Number: A-001-1440-3 • Date Posted: 29 June 2015
Gübelin, E.J. (1973) Internal World of Gemstones. Zürich, ABC Verlag, reprinted 1983, 234 pp.; RWHL*.
Hughes, R.W. (1997) Ruby & Sapphire. Boulder, CO, RWH Publishing, 512 pp.; RWHL*.