The Australian share market is back on form on Thursday and pushing higher.

But few shares are rising as much as Aldoro Resources Ltd (ASX: ARN) shares.

At the time of writing, the ASX small cap stock is up 53% to 39 cents.

What is Aldoro Resources?

Aldoro Resources is a mineral exploration and development company with a portfolio of critical minerals projects. This includes rare earth, lithium, rubidium and base metal projects.

The ASX small cap's projects include the Kameelburg REE & Niobium Project in Namibia, the Wyemandoo lithium-rubidium-tungsten project, the Niobe lithium-rubidium-tantalum project, and the Narndee Igneous Comples project in Western Australia.

Why is this ASX small cap stock rocketing?

Investors have been scrambling to buy the mineral exploration company's shares this morning after it announced assay results from the Kameelburg REE & Niobium Project in Namibia.

According to the release, the assay results for line 3 of the pre-drill sampling program have been received. They have confirmed that niobium mineralisation has been found across the 220 meters of line 3 at an average grade of 0.70% Nb₂O₅.

It notes that 190 meters of line 3 is entirely mineralised with niobium with grades that have exceeded the assays received for line 4. They are highlighted by 128 meters at 0.96% Nb₂O₅, including 90 meters at 1.12% Nb₂O₅.

Line 3 is located approximately 500 meters to the southwest of the previously reported line 4. An additional 168 meters of this line is still to be reported once those assays are received.

The company is also looking for rare earths. It notes that samples for lines 1, 2, 5, 6, and 7 have been received by its assay laboratory, the Center of Modern Analysis and Testing Central South University, and results for Nb₂O₅ and the associated rare earth suite of elements will be reported once received.

What is niobium?

Niobium is a critical metal that has properties that make it essential as the world transitions to a low-carbon economy.

Ferroniobium is the primary saleable form of niobium. It represents approximately 90% of established niobium sales globally at present. It is used mainly as a micro-alloy in steelmaking, providing significant improvements in strength, corrosion resistance, and heat resistance on the alloyed steel.

This makes it an essential ingredient for significant construction projects, automotive applications, wind turbines, and oil and gas pipelines and storage.

Investors appear optimistic that the small cap ASX stock could be sitting atop a sizeable deposit of the critical metal. But time will tell if that is the case.