Keris from Jogjakarta

[Marcokeris]

Originally Posted by David

How can you tell they are yakut just from the photo? They look like they could be quartz crystal just as easily. Or is yakut just a different name for quartz. I have always understood it to refer to low quality diamonds, but when i google it (yakut gemstone) i find no reference to diamond (except on account that diamonds where once mined in Yakutia). In some places it refers to a form of sapphire. In other places it is a ruby. Both of these are corundums, not diamonds. I understand that in Turkish it simply means gemstone.
I have a feeling that very often simple quartz crystal is passed off as "yakut". Is this the same as garnet being accepted as a form of ruby in this area? Can anyone tell me exactly what they are supposed to be in Indonesia in regards to keris?

Sorry David you are right.
I have alwawys considered yakut as simple quartz stone.
Low class diamonds are a different reflection/refraction: much more active (light's game seems to come from inside the stone)
On the contrary Zircon's light seems to me cold and unreal (too much cut sides on the stone)