| NASA discovered them on Mars in 2008 | 36 |
| Milky-white minerals | 20 |
| Milky white gems | 16 |
| Milky birthstones | 17 |
| Menilites, e.g. | 15 |
| Menilites | 9 |
| Libran birthstones | 18 |
| Iridescent stones | 17 |
| Hyalite and harlequin | 21 |
| Girasols, e.g. | 14 |
| Gifts on October birthdays | 26 |
| Geyserites | 10 |
| Gemstones from South Australia | 30 |
| Gemstones from Australia | 24 |
| Gems usually without facets | 27 |
| Gems that may be black | 22 |
| Gems from Australia | 19 |
| Fiery gemstones | 15 |
| Crown jewels | 12 |
| Crown insets | 12 |
| Black and fire followers | 24 |
| Birthstones whose name starts with the same letter as their month | 65 |
| Birthstones for some Scorpios | 29 |
| Autumn stones | 13 |
| Australian minerals | 19 |
| 80% of them come from South Australia | 37 |
| Muddy | 5 |
| Opposite of transparent | 23 |
| Not transparent | 15 |
| Impossible to see through | 25 |
| Not translucent | 15 |
| Not quite transparent | 21 |
| Not allowing light to pass through | 34 |
| Light-blocking | 14 |
| Obscure or dark | 15 |
| Not sheer | 9 |
| Not easily understood | 21 |
| Lacking clearness | 17 |
| Hardly transparent | 18 |
| Completely obscure | 18 |
| Clear as mud, so to speak | 25 |
| In an unclear way | 17 |
| Dizzying designs | 16 |
| Dizzying genre | 14 |
| Swirly prints | 13 |
| Eyeball-bending pictures | 24 |
| Eyeball-bending drawings | 24 |
| Illusory painting genre | 23 |
| Eye-popping prints | 18 |
| Abstract style of the '60s | 30 |
| Abstract form prominent in the '60s | 39 |
| Visual illusion genre | 21 |
| Illusory works | 14 |
| Illusory display | 16 |
| Illusionary genre | 17 |
| Eye-bending pictures | 20 |
| Eye-bending designs | 19 |
| Dizzying pictures | 17 |
| Dizzying gallery fare | 21 |
| Dizzying gallery display | 24 |
| Abstract painting style of the '60s | 39 |
| Works with visual effects | 25 |
| Visual-illusion genre | 21 |
| Style of painting | 17 |
| Painting style that's visually teasing | 42 |
| Illusory paintings | 18 |
| Eyeball-bending genre | 21 |
| Eyeball benders | 15 |
| Eye-bending works | 17 |
| Dizzying paintings | 18 |
| Bridget Riley's genre | 25 |
| Bridget Riley genre | 19 |
| Visually teasing images | 23 |
| Victor Vasarely's genre | 27 |
| Victor Vasarely's "Zebras," e.g. | 46 |
| Swirly posters | 14 |
| Some psychedelic designs | 24 |
| Some museum displays | 20 |
| Some drawings that deceive | 26 |
| Some abstract works | 19 |
| Showy gallery display | 21 |
| Retro poster genre | 18 |
| Pictures that create illusions | 30 |
| Perceptual abstraction | 22 |
| Off-the-wall piece on the wall? | 31 |
| Mesmerizing designs | 19 |
| It often employs geometric patterns | 35 |
| Genre of Vasarely's "Zebras" | 42 |
| Eyeball bender | 14 |
| Eye-popping genre | 17 |
| Eye-popping canvases | 20 |
| Eye-catching works | 18 |
| Drawings that deceive | 21 |
| Dizzying visuals | 16 |
| Dizzying pix | 12 |
| Dizzying drawings | 17 |
| Dizzying display | 16 |
| Dazzling drawings of the '60s | 33 |
| Certain abstract paintings | 26 |
| Bedazzling museum works | 23 |