Gemstone : Borneo Green Obsidian

Source :

http://www.google.co.id/search?q=green+obsidian+kalimantan&prmd=ivns&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiJmMyu0ZDQAhUFOo8KHaQrBzQQ_AUIBigB#mhpiv=15

Green obsidian is natural volcanic glass,formed as an extrusive igneous rock. It is produced when lava flow from a volcano cools rapidly with minimum crystal growth. This stone has mineral silicon diokside with level 5,5 hardness.

Obsidian is brittle,if it fracture will have sharp edge,the native of american use it for stab weapon. The other civilization transform this stone into knife for surgery.

Source :

http://www.google.co.id/search?q=green+obsidian+rough&tbm=isch&oq=green+obsidian+rough&gs_l=mobile-heirloom-serp.1.0.0j0i24.115600.121160.0.122503.21.15.3.2.2.3.271.2518.5j4j6.15.0....0...1c.1.34.mobile-heirloom-serp..7.14.1804.WwSu3GhVs5U#mhpiv=17

Martapura city is in Banjar district,south Borneo,there is famous gemstone market called pasar batu martapura or martapura gemstone market. The green obsidian was sold there and has market name : zamrud Kalimantan / Borneo Emerald.

Because the wonder green color,people suppose it is an emerald but it doesn't. Because green obsidianand green emerald are different kind of stone with different mineral and hardness level,very similiar but different. Green obsidian is not category of first class gemstone like diamond,ruby or sapphire. But this one is cheap and can be found easily.

Source :

http://www.google.co.id/search?q=green+obsidian+kalimantan&prmd=ivns&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiJmMyu0ZDQAhUFOo8KHaQrBzQQ_AUIBigB#mhpiv=5