A copper-bearing, approximately dioctahedral, smectite with a chemical composition of Ca0.20K0.01(Fe3+0.83Cu0.84Mg0.67Zn0.02Al0.01)Σ=2.37Si4O10(OH)2. Yakhontovite occurs in highly oxidized sulfide-cassiterite ores at the Pridorozhnoye deposit of the Komsomolsk district, Khabarovskiy Kray, Far-Eastern Region, Russia (Postnikova et al., 1986).
A member of the true mica group with an ideal composition of KMg2.5Si4O10F2, with possible substitution of 30% Li in the interlayer site. It is characterized by the Mg dominance over Fe, which is characteristic of montdorite. Material suitable for single crystal study has not been found. The type locality is in metamorphosed carbonate rock from Bayan Obo, Inner Mongolia, China (Miyawaki et al., 2011).
The phenomenon where a clay undergoes the transition from a purely elastic deformation stage to an elasto-plastic deformation stage. Yielding marks the onset of plastic deformation, and the stress at which yielding occurs is called yield stress or yield strength.
A member of the palygorskite-sepiolite group with a composition of approximately ~(R2+,R3+,v)5 Si8O20(OH, H2O)2(H2O)7, where Mn2+ dominates; R represents a cation and v are vacancies.
See palygorskite-sepiolite group
A measure of the response of a homogeneous material to uniaxial tension or compression, in units of pressure (usually gigapascals), obtained from the slope of the (linear) relationship of stress versus strain in the elastic regime.
Cf., elastic constants