Avi’s 8th Grade Science Class Experiment: “How does the elemental composition of glass marbles affect their color?”
Photos by Avi B. Rubin, age 14
(8th grade science, Sellwood Middle School)
Below each marble image is the full XRF test result for that particular color (& style) marble. These marbles are all from the manufacturer Marble King.
Important points to note:
- A Niton XL3T XRF instrument was used for this testing.
- All testing was done in “Consumer Goods” mode.
- Each XRF test was done for a minimum of 60 seconds.
- The results are replicable and accurate.
- The instrument was freshly calibrated prior to the tests being done.
- The tests were done with a fully charged battery in the instrument.
- The marbles tested were newly purchased and had not been used or played with (limiting the potential for external sources of contaminants.)
- The marbles were tested against a background that was tested first and confirmed not to test positive for any metals.
- Metals not detected in consumer goods mode are not listed.
- Note: on swirl marbles when the colored part of the marble was closer to the XRF scope (turned towards vs. turned away) many of the metals readings were higher (demonstrating that the metals are in the colors more so than in the clear elements.)
This is supporting documentation for my 8th grade science class research report.
Avi Rubin
#LeadSafeMamasKid
Solid Blue Marble (pictured above):
- Lead (Pb): 27 +/- 10 ppm
- Barium (Ba): 393 +/- 46 ppm
- Antimony (Sb): 344 +/- 21 ppm
- Zinc (Zn): 78 +/- 20 ppm
- Copper (Cu): 100 +/- 34 ppm
- Iron (Fe): 408 +/- 126 ppm
- Vanadium (V): 151 +/- 24 ppm
- Titanium (Ti): 350 +/- 41 ppm
- Cobalt (Co): 357 +/- 80 ppm
Continue reading below next image.
Orange Swirl Marble (pictured above):
- Lead (Pb): 92 +/- 11 ppm
- Cadmium (Cd): 345 +/- 12 ppm
- Barium (Ba): 1,414 +/- 52 ppm
- Antimony (Sb): 1,058 +/- 30 ppm
- Tin (Sn): 28 +/- 10 ppm
- Zinc (Zn): 4,243 +/- 117 ppm
- Iron (Fe): 396 +/- 93 ppm
- Vanadium (V): 321 +/- 33 ppm
- Titanium (Ti): 649 +/- 54 ppm
- Indium (In): 20 +/- 7 ppm
Continue reading below next image.
Yellow Marble (pictured above):
- Lead (Pb): 152 +/- 17 ppm
- Cadmium (Cd): 198 +/- 20 ppm
- Barium (Ba): 13,500 +/- 400 ppm
- Antimony (Sb): 3,439 +/- 84 ppm
- Zinc (Zn): 182 +/- 30 ppm
- Copper (Cu): 58 +/- 27 ppm
- Iron (Fe): 463 +/- 75 ppm
Continue reading below next image.
Clear Marble (pictured above):
- Barium (Ba): 859 +/- 55 ppm
- Antimony (Sb): 548 +/- 26 ppm
- Zinc (Zn): 7,321 +/- 228 ppm
- Vanadium (V): 233 +/ 31 ppm
- Titanium (Ti): 423 +/- 48 ppm
Continue reading below next image.
Green Swirl Marble – small (pictured above):
- Lead (Pb): 175 +/- 15 ppm
- Barium (Ba): 871 +/- 48 ppm
- Antimony (Sb): 869 +/- 29 ppm
- Tin (Sn): 119 +/- 13 ppm
- Zinc (Zn): 527 +/- 39 ppm
- Iron (Fe): 516 +/- 113 ppm
- Vanadium (V): 506 +/- 45 ppm
- Titanium (Ti): 1,121 +/- 79 ppm
- Indium (In): 19 +/- 8 ppm
Continue reading below next image. 
Brown Clear Marble (pictured above):
- Lead (Pb): 46 +/- 16 ppm
- Cadmium (Cd): 39 +/- 8 ppm
- Barium (Ba): 541 +/- 51 ppm
- Antimony (Sb): 584 +/- 28 ppm
- Zinc (Zn): 3,718 +/- 145 ppm
- Copper (Cu): 103 +/- 36 ppm
- Iron (Fe): 3,696 +/- 270 ppm
- Vanadium (V): 173 +/- 29 ppm
- Titanium (Ti): 356 +/- 47 ppm
- Manganese (Mn): 1,785 +/- 285 ppm
Continue reading below next image.
Green Swirl Marble – Large (pictured above):
- Lead (Pb): 1,375 +/- 51 ppm
- Cadmium (Cd): 18 +/- 7 ppm
- Barium (Ba): 393 +/- 55 ppm
- Antimony (Sb): 3,437 +/- 110 ppm
- Tin (Sn): 193 +/- 17 ppm
- Zinc (Zn): 278 +/- 34 ppm
- Copper (Cu): 145 +/- 38 ppm
- Iron (Fe): 467 +/- 134 ppm
- Vanadium (V): 129 +/- 25 ppm
- Titanium (Ti): 356 +/- 44 ppm
- Indium (In): 57 +/- 12 ppm
Continue reading below next image. 
Blue Swirl Marble (pictured above):
- Lead (Pb): 123 +/- 15 ppm
- Barium (Ba): 1,021 +/- 57 ppm
- Antimony (Sb): 972 +/- 35 ppm
- Tin (Sn): 272 +/- 17 ppm
- Zinc (Zn): 360 +/- 36 ppm
- Iron (Fe): 436 +/- 122 ppm
- Vanadium (V): 476 +/- 42 ppm
- Titanium (Ti): 1,086 +/- 76 ppm
- Indium (In): 22 +/- 9 ppm
Continue reading below next image.
Green Clear Marble (pictured above):
- Lead (Pb): 323 +/- 24 ppm
- Barium (Ba): 1,766 +/- 80 ppm
- Antimony (Sb): 796 +/- 34 ppm
- Tin (Sn): 102 +/- 16 ppm
- Zinc (Zn): 2,232 +/- 106 ppm
- Copper (Cu): 179 +/- 41 ppm
- Iron (Fe): 524 +/- 140 ppm
- Vanadium (V): 392 +/- 38 ppm
- Titanium (Ti): 851 +/- 67 ppm
Continue reading below next image.
White Swirl Marble (pictured above):
- Lead (Pb): 36 +/- 12 ppm
- Cadmium (Cd): 40 +/- 8 ppm
- Barium (Ba): 1,324 +/- 70 ppm
- Antimony (Sb): 766 +/- 34 ppm
- Tin (Sn): 102 +/- 16 ppm
- Zinc (Zn): 2,232 +/- 106 ppm
- Copper (Cu): 179 +/- 41 ppm
- Iron (Fe): 524 +/- 140 ppm
- Vanadium (V): 392 +/- 38 ppm
- Titanium (Ti): 851 +/- 67 ppm
Below is a picture of the two green swirl marbles next to each other so you can see how they are different. I will be working on a chart and a graph to help see the correlation between the metals found in relation to the different colors of the marbles.
Avi Rubin
See additional images below, including images of original packaging for these marbles.
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I thought Marble King marbles were supposed to be lead-free. 🙁
Yeah – nope! I have to write a post about that!
They sent their lawyers after me after I found Lead in their Lead-free marbles and then they changed all of their branding and language on their site but then they seem to have not told their vendors / distributors (in a way that was understood) as I still frequently see claims that this brand is Lead-free when listed by vendors.
Tamara
Lawyers after you?!? For the truth?!? There are no words! I just want to say thank you!!! Because of your info I have thrown away old plates/cups/toys and completely changed what I let my kiddos play with. My hubby and I really, really appreciate what you do!