Chrome black.
This is a color that appear in a single set, the Chrome Darth Vader, a promotional polybag released in 2009 with a limit of 10,000. This single minifig seems to be going to about $130 on the secondary market (bricklink).
It’s 1.07 g/cm3 according to the ABS density (ABS is what Lego are made of). It’s slightly greater than 1 and is the reason why Lego bricks don’t float.
But it’s actually not that simple as Lego constructions are usually full of air.
Consider the most common Lego piece, the venerable 6141 (aka round plate 1×1), it can be carefully packed or just thrown together. Different values are valid depending on the arrangement and what you’re trying to use it for.
| Arrangement of round plates | Density (g/cm3) |
| Lego legal packing | 0.55 |
| Optimal packing | 0.64 |
| Bulk | 0.42 |
Mode details about the computations.
Lego legal packing: a single round plate is about 0.113 g and occupies a space of
Optimal packing: here you put the plate in triangular tiling, so the space used by a single piece is
Optimal packing
Bulk: in a liter, you can put about 3735 round plates which translate into 422g/L or 0.42g/cm3.
There are several way to define what is a common piece. Ideally, that would be the based on the number of each type of piece available in the entire universe.
But given that the Lego Group doesn’t release how many pieces of each type were produced and that it’s hard to estimate how many ended up in vacuum cleaner and ultimately incinerated, we’ll have to accept some approximation.
Here I’m just taking a list of 5400 recently released lego sets (let’s say in the past 15 years) and count how many of each type of piece was in each set. Based on that, here is a list of the 100 most common pieces:
| 6141 |  |
|
| 3023 | Plate 1 x 2 |  |
| 3004 | Brick 1 x 2 |  |
| 2780 | Technic, Pin with Friction Ridges Lengthwise WITH Center Slots |  |
| 3024 | Plate 1 x 1 |  |
| 3005 | Brick 1 x 1 |  |
| 3003 | Brick 2 x 2 |  |
| 54200 | Slope 30 1 x 1 x 2/3 |  |
| 3710 | Plate 1 x 4 |  |
| 3069b | Tile 1 x 2 with Groove |  |
| 3020 | Plate 2 x 4 |  |
| 3001 | Brick 2 x 4 |  |
| 3010 | Brick 1 x 4 |  |
| 3022 | Plate 2 x 2 |  |
| 6558 | Technic, Pin 3L with Friction Ridges Lengthwise |  |
| 2412b | Tile, Modified 1 x 2 Grille with Bottom Groove / Lip |  |
| 3062b | Brick, Round 1 x 1 Open Stud |  |
| 3021 | Plate 2 x 3 |  |
| 3666 | Plate 1 x 6 |  |
| 43093 | Technic, Axle Pin with Friction Ridges Lengthwise |  |
| 3070b | Tile 1 x 1 with Groove |  |
| 3040b |  |
|
| 2431 | Tile 1 x 4 |  |
| 3068b | Tile 2 x 2 with Groove |  |
| 3623 | Plate 1 x 3 |  |
| 3622 | Brick 1 x 3 |  |
| 32062 | Technic, Axle 2 Notched |  |
| 3009 | Brick 1 x 6 |  |
| 4274 | Technic, Pin 1/2 |  |
| 3795 | Plate 2 x 6 |  |
| 3002 |  |
|
| 3039 | Slope 45 2 x 2 |  |
| 6636 | Tile 1 x 6 |  |
| 3713 | Technic Bush |  |
| 2420 | Plate 2 x 2 Corner |  |
| 4070 | Brick, Modified 1 x 1 with Headlight |  |
| 3660 | Slope, Inverted 45 2 x 2 |  |
| 4519 |  |
|
| 32123b |  |
|
| 3665 | Slope, Inverted 45 2 x 1 |  |
| 3941 | Brick, Round 2 x 2 with Axle Hole |  |
| 4032a |  |
|
| 3460 | Plate 1 x 8 |  |
| 2357 | Brick 2 x 2 Corner |  |
| 32054 | Technic, Pin 3L with Friction Ridges Lengthwise and Stop Bush |  |
| 3034 | Plate 2 x 8 |  |
| 85984 | Slope 30 1 x 2 x 2/3 |  |
| 3794b | Plate, Modified 1 x 2 with 1 Stud with Groove (Jumper) |  |
| 3700 | Technic, Brick 1 x 2 with Hole |  |
| 98138 | Tile, Round 1 x 1 |  |
| 3794a |  |
|
| 4162 | Tile 1 x 8 |  |
| 59900 |  |
|
| 3008 |  |
|
| 4589 |  |
|
| 2877 | Brick, Modified 1 x 2 with Grille (Grill) |  |
| 87087 | Brick, Modified 1 x 1 with Stud on 1 Side |  |
| 30136 | Brick, Modified 1 x 2 Log |  |
| 6536 |  |
|
| 2654 | Plate, Round 2 x 2 with Rounded Bottom (Boat Stud) |  |
| 44728 | Bracket 1 x 2 – 2 x 2 |  |
| 87580 | Plate, Modified 2 x 2 with Groove and 1 Stud in Center (Jumper) |  |
| 6091 | Brick, Modified 1 x 2 x 1 1/3 with Curved Top |  |
| 59443 |  |
|
| 32028 | Plate, Modified 1 x 2 with Door Rail |  |
| 4286 | Slope 33 3 x 1 |  |
| 4477 | Plate 1 x 10 |  |
| 33291 |  |
|
| 3673 | Technic, Pin without Friction Ridges Lengthwise |  |
| 87079 | Tile 2 x 4 |  |
| 2540 | Plate, Modified 1 x 2 with Handle on Side – Free Ends |  |
| 3705 | Technic, Axle 4 |  |
| 50950 | Slope, Curved 3 x 1 No Studs |  |
| 6541 | Technic, Brick 1 x 1 with Hole |  |
| 970c00 | Hips and Legs |  |
| 11477 | Slope, Curved 2 x 1 No Studs |  |
| 32013 | Technic, Axle and Pin Connector Angled #1 |  |
| 60478 | Plate, Modified 1 x 2 with Handle on End – Closed Ends |  |
| 53451 | Barb / Claw / Horn – Small |  |
| 3037 | Slope 45 2 x 4 |  |
| 2456 |  |
|
| 48336 | Plate, Modified 1 x 2 with Handle on Side – Closed Ends |  |
| 32073 | Technic, Axle 5 |  |
| 3031 | Plate 4 x 4 |  |
| 3749 | Technic, Axle Pin without Friction Ridges Lengthwise |  |
| 63864 | Tile 1 x 3 |  |
| 3065 | Brick 1 x 2 without Bottom Tube |  |
| 32523 | Technic, Liftarm 1 x 3 Thick |  |
| 32316 | Technic, Liftarm 1 x 5 Thick |  |
| 3032 |  |
|
| 3437 |  |
|
| 30374 | Bar 4L (Lightsaber Blade / Wand) |  |
| 32140 |  |
|
| 15573 | Plate, Modified 1 x 2 with 1 Stud with Groove and Bottom Stud Holder (Jumper) |  |
| 3832 | Plate 2 x 10 |  |
| 4740 | Dish 2 x 2 Inverted (Radar) |  |
| 3298 | Slope 33 3 x 2 |  |
| 4081b | Plate, Modified 1 x 1 with Clip Light – Thick Ring |  |
| 30414 | Brick, Modified 1 x 4 with 4 Studs on 1 Side |  |
| 41677 | Technic, Liftarm 1 x 2 Thin |  |
| 32524 | Technic, Liftarm 1 x 7 Thick |  |
