Trapiche

Trapiche emerald from the Muzo mine, Colombia

Trapiche morganite from Chamachhu, Pakistan

Trapiche ruby ​​from Möng Hsu, Myanmar

Trapiche cordierite ( cerasite ) from Kameoka, Japan

Trapiche is a term from mineralogy and crystallography and describes a special form of growth in minerals .

Etymology and history

The trapiche shape is similar in cross-section to a roller with gear wheels and was named after the Spanish word "trapiche" for olive or sugar mill (also known as stamp mill ).

The trapiche shape was first discovered in Colombian emeralds . It was named because of its similarity to the sugar mills and rollers operated in the country where it was found.

morphology

In the case of a trapiche crystal , six sectors arranged at a 60 ° angle are formed around a spindle-shaped central crystal . Fine-grained albite or calcite has grown into the gaps, which is often darkened by trapped organic substances such as black slate .

At right angles to the main or c-axis , such crystals show a star-shaped, wagon-wheel-like shape. The inclusions appear band-shaped parallel to the main axis.

Occurrence

By far the best known deposits of Tapiche crystals are the emeralds from Muzo in Colombia, however, like crystal forms are also other Beryl - varieties such as the Morganite known from Pakistan. In other mineral species such as, among others, the corundum -Varietäten ruby and sapphire , which discovered in Japan cordierite -Varietät Cerasit (also Sakura Ishi or cherry stone ), the various tourmalines and garnets , the andalusite -Varietät Chiastolith and the quartz observed.

use

In order to emphasize the specialty of the trapiche shape, the corresponding minerals are cut into cabochon form for use as gemstones . Because of their rarity, trapiche crystal shapes are very popular with collectors.

literature

• Rupert Hochleitner : The emerald: Mineralogically speaking, a beryl! In: Emeralds of the World. The beryl with the legendary green (= Christian Weise [Hrsg.]: ExtraLapis . Band 21 ). Christian Weise Verlag, 2001, ISBN 3-921656-58-3 , ISSN  0945-8492 , p. 14, 17 .
• Ulrich Henn: Gemstone Dictionary . Ed .: German Gemmological Society. Self-published, Idar-Oberstein 2001, ISBN 3-932515-24-2 , p. 93 .
• Jeffery Bergman: Trapiche: The Rising Star . In: InColor. All about colored Gemstones . Spring 2016, No. 31 , 2016 ( available online at gemstone.org [accessed June 25, 2018]).

Web links

Commons : Trapiche crystals  - collection of images, videos and audio files

• Isabella Pignatelli, Gaston Giuliani, Daniel Ohnenstetter, Giovanna Agrosì, Sandrine Mathieu, Christophe Morlot, Yannick Branquet: Colombian Trapiche Emeralds: Recent Advances in Understanding Their Formation. In: www.gia.edu. Gemological Institute of America (GIA), 2015, accessed June 25, 2018 . 
• Michael RW Peters: Cordierite, Cordierite Cat's Eyes and Trapiche Cordierite. In: realgems.org. December 26, 2010, accessed June 27, 2018 (with images of rough and cut stones). 

Individual evidence

1. ^ Walter Schumann: Precious stones and gemstones. All kinds and varieties. 1900 unique pieces . 16th revised edition. BLV Verlag, Munich 2014, ISBN 978-3-8354-1171-5 , pp. 100 .
2. ↑ Mindat - image of a trapiche sapphire
3. ↑ Cerasit (from Kikuchi) (also cherry blossom stone or Japanese Sakura Ishi )
4. ↑ Mindat - image of a trapiche tourmaline (Uvit)
5. ↑ Mindat - image of a trapiche quartz