...Peter J. Heaney; Edward P. Vicenzi; Subarnarekha De Abstract Polycrystalline aggregates of diamond called carbonado and framesite have excited the attention of scientists because their crystallization histories are thought to depart markedly from established modes of diamond genesis. In contrast...

...Figure 4 Carbon isotopic signatures for framesite diamonds from Orapa ( Deines et al, 1993 ), Venetia ( Jacob et al., 2000 ) and an unknown South African locality ( Dubosi and Kurat, 2010 ). The Orapa framesites are inclusion free, but the two other populations have websteritic inclusions. ...

...Sami Mikhail; Daniel Howell; Francis M. McCubbin Abstract A collection of 35 diamondite samples (polycrystalline diamond aggregates, sometimes referred to as framesites), assumed to be from southern Africa, have been studied to investigate their infrared (IR) spectroscopic characteristics. Due...

... and carbon isotopic signatures. Diamonds with complex growth zones and deformation textures can be explained in terms of dynamic mantle processes, linked to formation of the sheared peridotites, within the thermal aureole surrounding the kimberlite magma in which the megacryst suite crystallised. Framesites...

... polycrystalline diamond—carbonado and framesite—and, second, microdiamonds discovered over the last 20 years associated with metamorphic rocks. Heaney, Vicenzi, and De review the characteristics of carbonado and framesite and help unravel some of the mystery around these enigmatic materials. As a high-pressure...

... aggregates (framesites). Thus, the picrochromite is a signature indicative of its U/P-type (ultramafic) diamond environment. The only other reported occurrence of eskolaite to date is from the Zagadochnaya kimberlite in Yakutia, where it coexists with a set of eclogitic (E-type) Cr-enriched minerals...

..., irregularly shaped, polycrystalline aggregates with grain sizes ranging from less than 1 to several hundred μm ( Dismukes et al. 1988 ; Jeynes 1978 ; Trueb and de Wys 1971 ). Unlike non-porous microcrystalline diamond aggregates found in kimberlites (e.g., stewartite and framesite), carbonado is recovered...

... , 1998) and Corte et al . (1998) are plotted. Nitrogen concentrations in carbonado are higher than in impact-generated diamond, and lower than in cubic and metamorphic diamond. “Framesites” have similar nitrogen concentration to carbonado. ...

... ( Orlov, 1973 ) and Guaniamo ( Kaminsky et al., 2000 ; Sobolev et al., 1998 ) localities, respectively. Note that three samples belong to typical polycristalline aggregates (framesites) reported from many kimberlite pipes ( Kirkley et al., 1994 ; Orlov, 1973 ; Sobolev, 1974 ). Unlike the analyzed...

...., 2005 ), although they are in some respects similar to other polymineralic diamond varieties such as framesites and yakutites ( McCall, 2009 ). Carbonado is set apart from other diamond varieties by several unusual characteristics. The diamond material is texturally diverse, being dominantly...

... objective. Probably, the unusual smooth surface of the carbonado specimens can serve as a good discriminating criterion. Based on comprehensive isotopic analyses it was suggested ( Burgess et al. , 1998 ) that carbonado might be “an old framesite”, i.e. “common” polycrystalline diamond which underwent...

... as yakutite. Different hypotheses have been proposed for the origin of carbonado, including the following: transformation of organic sedimentary carbon into diamond in a cold subducted slab ( Robinson 1978 ), possible geochemical transformation of framesite into carbonado over time ( Burgess et al. 1998...

... of authors have proposed that polycrystalline diamond, for example “framesite” ( Heaney et al. 2005 ), containing silicate minerals whose isotopic and trace-element characteristics document remobilization of older carbon and silicate components, have crystallized shortly before kimberlite eruption ( e.g...

... – 587 . Kurat , G. & Dobosi , G. ( 2000 ): Garnet and diopside-bearing diamondites (framesites) . Mineral. Petrol . 69 , 143 – 159 . Kurat , G. , Palme , H. , Embley-Isztin , A. , Touret , J. , Ntaflos , T. , Spettel , B. , Brandstatter , F...