Re: Pre-Columbian Jadeite: Real?
Re: Pre-Columbian Jadeite: Real? -- CoinCoin Post Reply Edit Forum Where am I?
Posted by: frank Post Reply
01/12/2020, 21:02:54

Social jade in this case seems to include a lot of serpentine and some hydrogrossular garnet - chrome diopside mixes. Serpentine is listed as a very low hardness on the mohs scale but in the real world serpentines are often as hard as mohs 5 , the same as feldspar . If the geology provides the serpentine with an adequate infusion of quartz it can even go up to 6. In my area we have huge amounts of serpentine but only about 30% are in the expected 2 mohs range.With great wear the soft serpentine beads can show deformation from wear but with the harder serps this is not the case. Grossular garnet ( white ) and chrome diopside (green ) are very commonly found together and re fabulous for bead making as they are hard, 6 on the mohs scale. They can have brown and yellow areas of vesuvianite mixed in which is just as hard. A look alike for the grossular mix beads can be saussauritized gabbro in which the feldspar component has metamorphosed from white to green.. Gabbros are often found adjacent to ophiolites which are the rocks containing much of the nephrite and serpentines of the world. The central American jadeites are of different origin from nephrites but both types of jade are associated with massive fault systems. Jadeite from meso - America often has a sugar like texture when quite pure but jadeite is infamous for being intergraded with feldspar. The big strong colored bead on the upper left looks like a harder serp and the strongly patterened bead next o the penny and down at the bottom look like grossular -diopside but I make very similar beads that can be either grossular- diopside or saussauritized gabbro. In the rough experienced stone people can easily tell the difference but when cut they can be confusing.

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