Faceting Spinel (Blackjack)

Prospecting Australia

Help Support Prospecting Australia:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I like the hardness and evenness of the cutting as it gives good control over the meet points but getting a good polish does take a bit of time. Decided to keep the step cut larger and add a small star facet. I was going to make them frosted for a bit of an experiment but ended up cutting them with my polishing lap to make them shine.

Have struggled with my final polishing lap getting contaminated by a chip of stone or a stray large bit of diamond and have left a few fine scratches in this stone, but I think it turned out well and I have a good appreciation for black spinel now.

Sorry the photo is a bit poor, this is the best I can do on my iPad after about 50 shots.

1542243360_6d78abd7-deed-4afe-a556-c1e7bf706d29.jpg

1542243711_ff3dad77-bce6-4c26-bfa4-662a05a1d453.jpg

1542243976_8aebaaac-6986-4797-8061-5e40b35add7b.jpg
 
Interesting stuff Wally, certainly looks good. Did you do an SG test before you started? I have a bunch of black material and when I did an SG some had the SG of Sapphire, some Spinel and one the SG of Zircon, maybe what we often think as Spinel is actually something different??
 
Dihusky said:
Interesting stuff Wally, certainly looks good. Did you do an SG test before you started? I have a bunch of black material and when I did an SG some had the SG of Sapphire, some Spinel and one the SG of Zircon, maybe what we often think as Spinel is actually something different??

Not yet, at some stage I will try to sort them out and can see some SG testing being done as I know I have some black sapphire in the mix.

Thinking I have some tin crystals in there as well. Most of the tourmaline and spinel is identifiable by the structural differences but the waterworn ones are guesswork.

Doing a streak test sorting might help sort as well.
 

Latest posts

Top