TinyTuesday 208 Mineral

I took quite a few photos in our garden today, of various flowers, many with visiting bees and hoped that one would do for TT until I checked this week's theme...which is mineral.  After not following the theme last week, I felt that I must make an effort: initially I thought of my collection of mineral stones would be good  but I have no idea where I've very carefully stored them.  Then I thought of jewellery .  I have several necklaces made with  mineral stones and I photographed three of them.  For my main shot I've chosen one made of amethysts, as I like the shot best although Wikepedia tells me that the stone is 'not a valid species', whatever that means.  I've added as an extra another necklace which features such a variety of stones that some must surely be valid!
Many thanks to ninniex for hosting this month.