dyed agate

[Berryb]

I have a hand cut agate, about 7/16ths. It looks too dark to be natural, but my reading tells me that dyed mibs were generally blue, green, yellow, or rarely, black. Is there any way to tell a dyed agate besides color? Thanks

Bruce

[machinemades]

I am not clear what you are asking but yours could be a different type of stone. It looks like a dark brown dyed banded agate but could be onyx. There are many different types of agates and other stones out there. If it has facets it is handcut. 

[bumblebee]

I have a couple that are this darker brown color with bullseyes. In my experience these are less common than the black and white "striped onyx" ones. Structurally they look just like other banded agates to me.

I glanced at the book Colonial Period and Early 19th-Century Children's Toy Marbles which says the Brazilian agates (which are naturally grey or or bluish-grey and were sold as "flinties") would first turn brown when left in the sun, then eventually red.

Perhaps this style of agate is just the brown stage of sun dyeing?

To my eye they are less appealing than the red ones. I don't recall seeing agate ware such as letter openers in this color either, but perhaps someone has.

What I couldn't find in the book are descriptions of the colors of locally mined agate used prior to the mass importation of South American agates starting around 1834.