When an ASX share, or perhaps an ASX gold stock, shoots up by 30% over just one month, it's usually enough to make most investors sit up and pay attention. You might also expect investors to be more likely to cash out some gains, and take money off the table, rather than doubling down after such a dramatic spike in value.

So let's see what's been going on with prospective gold miner Catalyst Metals Ltd (ASX: CYL)'s shares.

Catalyst Metal's share price has indeed risen by 30% over the past month – 31.8% to be precise. Yes, this ASX gold stock was being priced at just 66 cents a share this time last month. But today, those same shares will set an investor back 87 cents apiece.

Catalyst has risen even more dramatically since the beginning of March. On 4 March, Catalyst shares were worth just 50 cents each. That means investors in this ASX gold stock have enjoyed gains worth around 74% since then at today's pricing.

Despite these gains, two Catalyst directors have recently been spending up to acquire additional shares in the company.

An ASX filing from last Friday shows that both David Jones and James Champion de Crespigny have recently made large purchases of Catalyst Metals stock. Jones is the ASX gold stock's non-executive chair. Champion de Crespigny is none other than the company's managing director and CEO.

The filing reveals that Jones purchased 66,666 ordinary Catalyst shares (he's clearly not a superstitious man) through a holding company on 18 April last week in an on-market transaction. This buy set Jones back $50,165.

In Champion de Crespign's case, 1,333,333 shares of the ASX gold stock were purchased on 19 April. That was for a cost of $1 million. This purchase was made up of both direct buys and indirect purchases through trusts.

This takes Champion de Crespigny's stake in Catalyst Metals to roughly 3.7 million shares. That's in addition to 1 million performance rights.

Jones didn't have a position in Catalyst before this transaction. That's aside from the possession of 2 million unlisted options. However, Jones has only been in his chair role since October last year.

The ASX filing implies both Jones and Champion de Crespigny purchased their additional shares for an average price of 75 cents each. So they've already done very well on their purchases, judging by today's pricing of this ASX gold stock

But they have been executed at a price well above what Catalyst was trading at even a few weeks ago.

As such, shareholders will probably feel a boost of confidence with that knowledge, as it is arguably a big vote of confidence in the future of this prospective ASX gold stock.