The difference between opal and plastic opal, combination opal How to identify opal and plastic opal, combination opal opal and plastic opal, the difference between combination opal plastic imitation opal: plastic imitation opal, with a double structure.
The interior is polystyrene, and the exterior is coated with acrylic resin to create a Mosaic pattern of needle flames changing colors, very similar to natural fire Opal.
The density of plastic imitation opal is 1.21-1.26g/cm3, which is much lower than natural opal (density 2.15-2.23g/cm3).
It feels light in the hand.
Placed in glycerol (density 1.26g/cm3), the plastic mimics the opal to rise, while the natural opal to sink.
The plastic imitation Opal hardness is 1.5-3, while the natural Opal hardness is 5-6.5, which is very different.
Ordinary sewing needles can make marks on plastic imitation opals but not on natural opals.
Under the reflected light of incandescent lamp, the plastic mimics Opal as translucent light blue opal, and under the transmission light, the plastic mimics Opal as pink orange opal. Under the polarizer, there is no change in light and dark, and abnormal interference color.
How to identify opal and plastic opal, opal combination of opal: combination of opal for opal two layers of stone and Opal three layers of stone.
The KEY TO the identification is to observe from the waist or side of the gem. Different layers are different in color, luster, color sheet, transparency, etc., that is, there are signs of splicing, or joint lines, adhesions or bubbles.
A. Opal two-storey stone: the top surface with good quality opal, the bottom surface lined with black agate, black chalcedony, inferior opal or Opal surrounding rock, with black adhesive.
B. Opal three layers of stone: the top surface with colorless quartstone or glass and ground into a camber, the middle of the natural opal is also made into a camber, with colorless glue and top surface bonding, and then under it with colored glue on the black chalcedony, glass or inferior opal.
The identification of combinatorial opal is mainly to find the binding surface.
It IS EASY TO DETECT THE RING SURFACE OF THE combined gemstone without INlay. It is enough to observe the changes of color, luster, transparency and bubble on both sides of the joint surface with naked eye or magnifying glass.
Additional, viscose is softer, can decide with fine needle probe.
However, for the package of the bottom of the combination of gemstones, more difficult.
Available microscope, strong light from the mesa inspection.
If the difference between the two sides of the binding surface is not found, the fluorescent lamp can be used to detect the difference between the fluorescence displayed by the gemstone and the viscose.
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