A Photogallery of Red Emerald Disturbance Modifications
Last week, The Prismatic Habits of the Red Emerald evaluated the General Form of red beryl crystals as standard, unmodified hexagonal Prisms.
A Review of the Elements of the red beryl Prism.
Emerald Prisms must synthesize with the added stress of pneumatolytic pressure, creating altered beryl crystals which are vastly different than the typical products of pegmatitic growth. Additional pressure causes a mineral to fight harder against the greater number of solid and semi-solid components encountered within the low-temperature environment of a magmatic solution, forcing disruptions to the precise molecular order. Formation under pressure also inhibits size and increases damage to crystals.
Many adjustments were made to compensate for environmental conditions encountered during crystallization, and alterations to structure can be divided into two general categories:
Mirror-Modifications and Disturbance Modifications
Disturbance Modifications affect one face and/or the termination end in the direction of growth.
Complex alterations affect multiple crystal faces -- the next chapter of this blog will examine these Mirror-Modifications.
Land of the Finest Water
Think about holding a glass of water…now shake the glass. What happens to the ordinarily serene and flat surface of the water in the glass? Movement causes the surface to become uneven and disturbed. In a similar manner, movement during the millions-of-years-long process of crystallization may create disturbances to the General Form of beryl.
Disturbances cause "temporary" adjustments to crystal growth and may have been corrected by additional layers of continued crystallization; Disturbance Modifications are mostly superficial and non-pyramidal. While specimens so-modified typically present less dramatic architecture compared with more complex forms, some of the most fascinating natural patterns and habits for this rare and precious variety can also be observed in these structures.
As we shall commence to demonstrate!
The following modifications to crystal form are linguistically and visually defined in this Photogallery:
Etching
Striation
Facial Separation
Platform
Hexagonal Stacking
Hexagonal Grouping
Partial Plateau
Full Plateau
Scepter
These terms are used regularly in my descriptions of red beryl specimens.
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ETCHING
Etching of staggered Stair-Steps on the bottom of the left crystal face.
Etching. A noticeable variation in the surface topography of a crystal face, which may be caused by early-phase external modifications, mirror-plane pressures, unseen structures overlapping within the internal lattice or other unknown source of stress at the time of formation.
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STRIATION
Striations are a by-product of formation similar to the natural appearance of growth lines in fingernails.
Striation. Etched furrows on the surface of a crystal face roughly oriented parallel to the C-Axis, following the direction of growth.
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FACIAL SEPARATION
Facial Separations on the top and center faces of this matrix specimen.
Facial Separation. A secondary layer of crystallization which partially crosses the surface of a crystal face. Damage can lead to errors in orientation of the lattice, as shown above.
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PLATFORM
A thick, gem block Platform sticks to the bottom right face.
Platform. A secondary layer of crystallization which partially crosses the surface of a crystal face to rise more prominently than a Facial Separation.
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HEXAGONAL STACKING
The Hexagonal Stacking of more than half a dozen wafers can be observed.
Hexagonal Stacking. Slightly-raised profiles of small beryl wafers on the termination end of a crystal.
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HEXAGONAL GROUPING
Newly-attached wafers band together to raise their Hexagonal Group.
Hexagonal Grouping. Plates form at a slightly faster rate together, elevating their larger, shared, six-sided structure above the termination end by a thin margin.
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PARTIAL PLATEAU
Disturbances reveal hexagonal stacking and grouping to form a Plateau.
Partial Plateau. Two or more Hexagonal Groups rising simultaneously in competitive growth, with no group fully surrounded by any others. A Plateau can be thought of as a Platform on a Termination End.
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FULL PLATEAU
Newly-attached wafers band together and elevate their Hexagonal Group.
Full Plateau. This habit forms when a crystal shows preferential growth towards a specific group of wafers enclosed in the center of a termination end, allowing that hexagon to rise in obvious contrast with the mineral's primary architecture.
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SCEPTER
Hexagonal Groups work together to dramatically elevate into a Scepter.
Scepter. Pronounced Full Plateau surrounded by a larger crystal at one termination. A Reverse Scepter occurs when the larger crystal is at the bottom of a specimen (beginning of growth) like the spectacular example pictured above.
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Be on the lookout for these crystal modifications in beryl specimens you encounter in the digital and physical worlds!
The next photo-investigation of this blog will cover structural Red Emerald alterations, as we discover the amazing Mirror-Mods!