Special Collector Slabs
Agate is the banded form of the mineral Chalcedony, which is a micro crystalline variety of Quartz. Agate is the most varied and popular type of Chalcedony, having many varieties on its own. Some of our favorite "Special Slabs" are called "Turtleback Agate" slabs. What is a turtleback agate slab? you ask...good question. Turtleback is actually a version of a botryoidal formation.
Agate usually forms in rounded nodules or knobs which need to be sliced open to bring out the internal pattern hidden in the stone. Collectible forms of Agate include nodules (solidly filled agates) or geodes (agates with hollow or crystal centers) sliced in the middle into two polished faced halves, or thin slabs from nodule or geode cross-sections.
The formation of Agate occurs when layers of silica (chalcedony) are deposited and fill the voids in volcanic vesicles or other cavities. The layers form in distinct stages over long periods of time. Sometimes the new layers provide alternating colors depending upon the mineral influences of impurities in the chalcedony. These are called banded agates. Since the cavities are irregularly and uniquely shaped, each Agate forms a one of a kind pattern based on the original shape of the cavity. When a cavity is completely filled, it forms a solid mass of Agate, but often it is only partially filled, leaving a hollow void which often has crystalline Quartz growths in its vug.
What causes the botryoidal formation? Each sphere (grape) in a botryoidal mineral is smaller than that of a reniform (kidney shaped) mineral, and much smaller than that of a mammillary (large smoothly rounded masses) mineral. Botryoidal agates form when many specks of sand, dust, or other particles, are present. Layers of Chalcedony mineral materials are deposited radially around these particles. As more material is deposited, the spheres grow larger and eventually overlap with those that are nearby. These nearby spheres grow together to form a botryoidal cluster.
One of chalcedony's most unique characteristics is it's tendency to form botryoidal (grape-like) structures that form internally in agates as "turtle-backing" or sometimes externally as "bubble-top" surfaces. Some people refer to the turtleback appearance as "billow like" resembling clouds in the sky.
The slabs listed on this page are a collection of Special, rare and unique slabs we have collected over the years from 1969 to the present day...thought it was time to share some of our treasures with our loyal customers.
Item # 1SCS04160001
Banded and Turtleback Agate Slab
Beautiful Brown and Tan Turtleback Brazilian Agate with Banded section polished on 2 sides
Weighs 2 oz (61g) and measures 3 x 2.8 x 0.21 inches (78 x 71 x 5.36mm)
Item # 2SCS04160001
Banded and Turtleback Carnelian Agate Slab
Beautiful Brown and Tan Turtleback Brazilian Agate with Banded section Polished on 2 sides
Weighs 2.6 oz (75g) and measures 3.4 x 3.3 x 0.23 inches (86 x 84 x 6mm)
Item # 3SCS04160001
Banded and Turtleback Carnelian Agate Slab
Beautiful orange and Tan Turtleback Brazilian Agate with Banded section Polished on 2 sides
Weighs 1.9 oz (55g) and measures 3.2 x 2.8 x 0.21 inches (83 x 71 x 5.36mm)
Item # 5SCS04160001
Turtleback Agate Slab
Beautiful dark edge smokyTurtleback Brazilian Agate Polished on 2 sides
Weighs 1.8 oz (52g) and measures 3 x 2.8 x 0.2 inches (78 x 71 x 5.2mm)
Item # 7SCS04160001
Turtleback and Banded Agate Slab
Beautiful dark edge clear to smoky Turtleback Brazilian Agate with small drusy vug Polished on 2 sides
Weighs 4.1 oz (117g) and measures 5 x 4.3 x 0.16 inches (128 x 109 x 4.25mm)
Item # 8SCS04160001
Turtleback India-like Agate Slab
Beautiful Brazilian White Skin Agate with dark India Agate-like floaters with Turtleback Brazilian Agate. Polished on 2 sides
Weighs 2 oz (58g) and measures 3.8 x 3.5 x 0.14 inches (97 x 89 x 3.7mm)
Item # 13SCS06160001
Very Rare Orpheus Agate Slab
Orpheus Agate is a very rare variety of agate found in the Rhodope Mountains in Kardzhali Province, Bulgaria. In 2004 at the Rock and Mineral exhibition in Munich, Germany It was determined that the “Orpheus Agate” is a unique new find in the world and is only found in Bulgaria. The Orpheus Agate is generally banded with Green Seladonit (a soft green earthy mineral consisting of silicate of iron, magnesium, and potassium) and brown and yellow jaspers. There is a clear to white Chalcedony which may often contain dendritic moss inclusions producing fabulous landscape effects. This slab is polished on one side, making it an excellent display piece.
This specimen weighs 2.42 oz (69g) and measures 5 x 1.1 x 0.34 inches (127 x 30 x 8.8mm)