![]() |
Abstracts Contents | |
Horváthite-(Y) Abstracted by Robert Gault
Horváthite-(Y) has two distinct habits: it occurs as (1) stacks of (100) plates, approximately 1 x 1 x 0.25 mm and as (2) blocky aggregates of radiating crystals 1-5 mm across with individual, striated, prismatic crystals up to 1 mm long on [010]. The aggregates are commonly 'wagon-wheel' or cylindrical in habit. Horváthite-(Y) is colourless to pale beige, translucent to transparent with a vitreous lustre. It is brittle, with very good {100} and good {010} cleavages. The mineral is relatively soft (Mohs hardness 4) and does not fluoresce in ultraviolet light. Dcalc. 3.613 g/cm3. It is biaxial negative, with indices of refraction a 1.457(1) b 1.543(1) and g 1.622(1); 2Vmeas. = 82(1)º (for l = 590 nm). The mineral is weakly pleochroic with Y » Z pale brown, and X colourless. Horváthite-(Y) is orthorhombic, space group Pmcn, a 6.959(2) b 9.170(2) c 6.301(1) Å, V 402.1(2) Å3 and Z = 4.
Source:Grice, J.D. & Chao, G.Y. 1997. Horváthite-(Y), rare-earth fluorocarbonate, a new mineral species from Mont Saint-Hilaire, Québec. Can. Min. 35:743-749.
This article may not be copied, distributed or reprinted in any form without the author's permission. To contact the author, please use the e-mail address provided. If you are unable to contact the author, please contact the Canadian Rockhound. Authorized reprints must acknowledge the author, original source and the Canadian Rockhound, and include the website URL address of the Canadian Rockhound. Document Number: CR9802104
![]() ![]()
Copyright © 1998 Canadian Rockhound
Magazine Issues |
News & Events |
Junior Rockhound |
Resources |