Please join the Calgary Mineral Exploration Group on Friday, February 7th for a talk given by Dr. Mike Menzies

If you would like to attend the luncheon, please RSVP by email at megcalgary@gmail.com or by selecting one of the options below.

**Please RSVP as soon as possible to accommodate everyone for lunch.

If you’d like to pay the Membership or Luncheon fee online, please click on the appropriate link below to be redirected to the secure Square website. Otherwise cash payment is available at the door.

Luncheon Details:

Date: Friday, February 7th, 2025
Location: Kerby Centre – downtown Calgary (1133 – 7th Ave. SW)
Doors open at 11:30 am
Talk starts at 12:00 pm (NOTE TIME FOR THIS LUNCHEON)
Membership:
$25
Luncheon for Members: $30
Luncheon Non-members: $35
Talk and Beverage (Coffee, Juice, Pop): $10
University, SAIT, NAIT students: FREE with student ID (with purchase of membership)

NOTE: There is complimentary parking at the Kerby Centre. Parking lots are located beside the building (east) or across the LRT (North). Register your vehicle at Reception.

Presentation Abstract:

The objective of the presentation is to provide an introduction to Gemstone-Bearing Pegmatites.

Pegmatites are produced from the very last remnants of some granitic magmas, and are most commonly recognized by their exceptionally coarse grain size.

Those that host gem crystals are rare, representing a very small proportion of the overall pegmatite population, and are typically confined to specific districts. Key characteristics include shallow emplacement depth, which helps to create the required open space (miarolitic cavities) for the crystals to grow. The most widely accepted classification (introduced by Petr Černy (in 1991), divides pegmatites into two families, NYF and LCT, which are named for their characteristic trace elements (Niobium, Yttrium and Fluorine and Lithium, Cesium and Tantalum).

Most NYF bodies have crystallized within their parent granites vs. LCT pegmatites, which are emplaced within the surrounding country rocks. Despite the difference in the characteristic trace elements, there is significant overlap between the families in their chemistry and the corresponding gem minerals. Of the two families, NYF pegmatites are typically much less well represented in the literature than those of LCT Family, with some of their features also less well-understood. But, some characteristics (e.g., diversity of size, physical form & internal structure) make them more interesting than their LCT counterparts. Although NYF bodies are mostly significantly smaller than LCT types, a small proportion are exceptionally large and some produce the world’s best and largest crystals of gem minerals.

The final portion of the presentation focuses on a few specific NYF localities and their pegmatite structures and miarolitic cavities.

Presenter Bio:

Dr. Mike Menzies

Mike was born and grew up in New Zealand. He graduated there as an engineer in 1966 before emigrating to Canada, where he obtained a PhD in Chemical Engineering at McMaster University in Hamilton, Ontario in 1972. After a few years in Montreal, he moved to Calgary in 1976. There he spent the remaining decades of his career in the Alberta Petroleum Industry as an engineer, project manager, and finally a consultant, before he retired in 2010. After moving to Calgary, he became an avid mineral collector, and in subsequent decades has field collected in Alberta and Quebec, Idaho, Montana, Utah, Nevada and California.

He has written for the Mineralogical Record on the worldwide occurrence of topaz, and authored locality articles for the Mineralogical Record and Rocks & Minerals. Since 1990, he has been a speaker at mineral shows and mineralogical symposia in Canada and the USA. His quest for knowledge about pegmatites and their gem minerals has taken him on international trips to Elba and Madagascar for mineralogical symposia and field excursions. In 2022, the Mineralogical Association of Canada published his book (co-authored with the photographer, Jeff Scovil), “Pegmatites and their Gem Minerals” as Special Publication No. 15 of the Canadian Mineralogist.