Description: Lapidary Deep drill bits do exactly as the title implies- they are for drilling through significant amounts of material.
They appear to be Siamese posts, or a figure 8 if you look down at them from the tip.
Thumb size Quartz crystals, or anything over standard slab thickness (4mm) should be drilled with these.
These are designed to let more water in as lubricant, and the shaft is thin so it can follow in behind the drilling action.
Other drill bits will strip due to heat build up and friction if you drill anything thicker than standard slab thickness- even when drilling with the stone fully submerged in water.
These are Diamond Plated
I recommend starting the hole with a Solid Post (Thick) drill bit first- to create a "center punch" type mark.

Made In: China

MEASUREMENTS:
1mm Bit: Length: 3.8cm  Shaft Thickness: 0.5mm
1.25mm Bit: Length: 3.7cm  Shaft Thickness: 0.5mm
1.5mm Bit: Length: 4.3cm  Shaft Thickness: 0.7mm
2.3mm Bit: Length: 5.3cm  Shaft Thickness: 1mm

Quantity: 5pcs all the same size